You get familiar with the voice of God not by spending time in hearing the enemy's voice, or the world's voice, or the voice of your own flesh, but by spending time in God's Word and in quiet times with Him. And this is the most important step in recognizing that a prophetic word delivered by someone else is from God. You are not left to chance to figure if a word is from God or not, God has placed the Holy Spirit in you to keep you connected with God, and knowing His will. He has given you Scripture to familiarize yourself with His voice, mind (what He thinks), heart (what He feels), ways (How He acts), and His timing. 

One day you will be the one standing before God on judgement day. And it is to Him that you must give account for what you did based on what He asked you to do. We get to know His voice so that we can assume the primary responsiblity, as intended by God, to know and discern His will for our lives. The prophetic words of others are given to affirm and confirm what God is revealing to you, in intimacy. But it will always be your responsibility to discern/judge the word. Keep what is of God and reject what is not. 

"My sheep listen to my voice; I know them, and they follow me." - John 10:27 NIV

"Do not quench the Spirit. Do not treat prophecies with contempt but test them all; hold on to what is good, reject every kind of evil." - 1 Thessalonians 5:19-21 ESV

"Let two or three people prophesy, and let the others evaluate what is said." - 1 Corinthians 14:29 NLT

"Now the Berean Jews were of more noble character than those in Thessalonica, for they received the message with great eagerness and examined the Scriptures every day to see if what Paul said was true." - Acts 17:11 NIV

"No prophetic word should disagree with the written Word of God. In fact, the church should actively examine prophetic utterances to make sure that they are in line with God's Word and boldly toss out any that are not. For example, if a person prophesies that a married person is to leave their spouse and marry someone else, that prophecy is a blatant deception and witchcraft is at work. If a renegade tries to prophesy to a church member that God wants them to rebel against the leaders, again, this prophecy is a deception and false spirit. Never accept a prophetic word that cannot be properly judged by God's Word." - Ryan LeStrange

"When it comes to your own personal ministry and destiny, you have a right and a responsibility to discern what is of God and what isn't." - Larry Randolph

"You gotta respect and honor the word of God, over the word of man." - Larry Randolph

But remember this: Part of judging a prophetic word may also be you saying to yourself, "At this point in my life, I don't have enough information or experience with what was said about me or about my destiny to decide if this word is from God or not." This means, for some words, you will put them on a "mental" shelf (though you should have it written down to not lose the wordage and specifics), where in the future, you may go back and access them to test them again. If if is a word of prophecy (meaning about your future), time will tell. You may in time begin receiving revelation from God or events will unfold that will start to define for you more of your destiny as it relates to that word. So then you are more able to judge it. Some words of prophecy will require patience and time. 

In Genesis 37:5-11, young Joseph shares his two dreams about his brothers and parents bowing down to him. What Joseph should have done is kept the prophecy to himself as he already had a poor and tense relationship with his step-brothers. As soon as they heard the first word, his brothers shot down the prophecy as not from God, but as sourced from his pride. "His brothers said to him, 'Do you intend to reign over us? Will you actually rule us?' And they hated him all the more because of his dream and what he had said." (Genesis 37:8) In the sharing of the second dream, though Abraham, his father, rebuked Joseph, in the end he did not let go of the prophecy. He more or less pondered it in his heart, over time, not letting go over it. He had in a sense not enough knowledge to rule it out. So he kept it close by in his mind for a later clarification. "When he told his father as well as his brothers, his father rebuked him and said, “What is this dream you had? Will your mother and I and your brothers actually come and bow down to the ground before you?” His brothers were jealous of him, but his father kept the matter in mind." (Genesis 37:10-11) This is what we aught to do with words of prophecy we cannot fully rule out. 

 See webpage: Testing a Prophetic Word

"Dear brothers and sisters, make sure that you show your deep appreciation for those who cherish you and diligently work as ministers among you. For they are your leaders who care for you, teach you, and stand before the Lord on your behalf. They value you with great love. Because of their service to you, let peace reign among yourselves." - 1 Thessalonians 5:12-13, TPT.

"The first question to ask is: 'Who gave you the word and how was it delivered?' Why is this important? Many times, a wrong word is evidenced by the way it is delivered. I have seen many 'parking lot prophets' who roam from church to church to engage in a renegade prophetic ministry that operates outside of any blessing from the house. This creates conflict by speaking to the ambitions of people instead of pure prophetic declaration. You should have some knowledge of a person's character before allowing them to speak into your life. People who claim to be prophets yet disrespect order, tearing down more than they ever build up, are indeed deceived. The problem that arises is that sometimes a deceived person still has an accurate gift that will draw people in." - Ryan Le Strange

"Ask yourself if the word confirms something you've already felt led to do. For example, a person owns a business that God clearly directed him to have and God told him that it is a place of fruitfulness and ministry for him. Then he gets a prophecy that he is to sell the business and start a church. He should never just run out and do that. If the prophetic word does not bear witness in the inner man, then either put it on the shelf, as it could be for a future time, or throw it out. Never make a major decision based on a single prophetic word without any leading of the Spirit in your own life!" - Ryan LeStrange

You are ultimately responsible to God for what you do with what He has shown you. The Lord is fully able to confirm His word and call on your life. 

For by wise counsel you will wage your war, and in multitude of counselors there is safety."  -(Proverbs 24:6 MEV)

Take the word you have received to trusted advisers and ask them to judge it. 

"When judging a personal prophecy, honor your spiritual relationships and seek the input of these trusted individuals. If your parents are godly people, ask them what they think. If you are married, and your spouse is serving the Lord, seek her/his input. The people who know you best and are committed to God's will for you can often see things that you may not see. Also, seek the input of your spiritual leadership. Go to your pastor or apostolic leadership and ask him for insight. So many times I have seen a prophecy steer someone in the wrong direction and then this person's lack of communication with godly leaders empowered the deception." - Ryan Le Strange

"Remember that the way Paul describes the New Testament spiritual gift of prophecy is not canon-level revelation [by canon-level, it is meant not at the level of the Biblical authors who were inspired by God to write the Scriptures] delivered infallibly and authoritatively like the Scriptures. The way he describes it... is Holy Spirit-prompted, subordinate revelation that readers of 1 Corinthians 14 and 1 Thessalonians 5:19–21 would expect to be partially or fallibly reported, and therefore intended to be tested against and subject to the infallible, authoritative revelation now contained for us in the sixty-six books of the Holy Bible. Paul expects New Testament prophecy, the kind he refers to in 1 Corinthians 14, to be fallibly — which means sometimes erroneously — delivered by people. Mistakes will happen, which is why prophecy must be evaluated." - John Piper

"God calls all Christians, including prophetically gifted ones, to submit to duly appointed local church leaders (Hebrews 13:17; 1 Corinthians 14:37–38). And in the case of prophecies, we also submit to the evaluation of our brothers and sisters in our local church (1 Corinthians 14:29–33)." - John Piper

"Many of God's people have fallen into deception by taking a prophetic word and adding their own interpretation to it. then saying God promised them this or that... Be careful not to take a word and run in a direction God has not ordained." - Chuck Pierce/Rebecca Wagner Systema

Confirmation words come to increase your faith. Activation words jump start something inside of you. Is there a notable change in your life after that word? Take note of it. This does not mean that all of it is fulfilled soon after. Many prophetic words take weeks, months, and at times years to see its fulfillment. But the seed of something new could have come with this word. It activated something in you, a new pursuit, a new perspective, a new action, or just plainly gave you something new you hadn't thought about, to consider or see it as a possibility. So you assess if it is a confirmation or an activation word to more clearly understand and discern God's purpose in what He has spoken to you. 

For me (Raimer), one powerful word I got in '95 gave me the perspective I needed for the many ensuing years that God had chosen to work on my character. The word I got, clearly emphasized that God was more focused on working on the inside of me than what I could do for Him. Here's a sentence from my longer word, "I am going to make you one of my breakthrough men as you allow me to breakthrough in you!" This word allowed me to position myself in a posture of humility and surrender to what God was doing as I walked through many challenges for 23+ years. I knew God was up to something and I just had to trust in His purposes and give up the need to control, manipulate, or take matters into my own hands to change my God-designed, life-shaping situation of the present—that which was especially designated for my own character development and spiritual growth.  

"...when trouble or persecution comes because of the word, they quickly fall away." - Mark 4:17b

This quote below is specific to the kind of prophetic words that speak to your destiny:

"Prophecy—the type that speaks of your destiny—highlights you. It puts God's spotlight on you... Satan is not God, he is not omniscient [all-knowing]. Only God knows everything. So [Satan] may not know how important you are or how crucial your life is. The moment prophecy comes [the destiny-type of prophetic word] it highlights who you are... And suddenly the enemy knows your potential and your destiny and what you are gonna do in this generation.... And some people who are not ready for the greatness that God has in you also begin to see or to hear what God is doing in you. And may be uncomfortable with it... Remember that persecution comes for the sake of the word, so that you forget that word, so that you doubt that word, so that you throw that word away. Because in the word of God is your destiny and your destiny is linked to so many other people... When prophecy comes the enemy becomes sure of the damage you will do to his kingdom so he raises hell hoping that you are now weak enough, scared enough to now forfeit the destiny that God has for you... People have a way of putting you in a box, of what they think you should be and the limits they think you should climb to. But now everything is changing [because of the word and you laying hold of it] and some people get jittery and restless because your lifting threatens their own position... The moment you receive prophecy yourself, fortify yourself in the word of God, fortify yourself in worship and prayer. You must be strong. You must be bold. You must be brave... Get ready for battle and know that you are more than a conqueror." - Judy Karanja (video)

Examples of Bible characters who had to war for their word: David and Joseph