Extrabiblical? Outstanding topic!
When the Lord called me out of my long backsliding, I started to glean teachings from all over the Internet. I used to comb the Net for podcasts of classroom instruction, historical stuff, and music. when I got rid of all of that, I wanted to replace it with God's stuff. MP3s were the rage and I knew the church was going to have a lot of it!
I downloaded over a terrabyte of teachings and testimonies. I'd find one site and the Lord would heighten my appetite. I could "tell" by the topics stuff the Holy Spirit wanted me to eventually give an ear to.
Then I read about the "civil war" in the Body of Christ. Very sad indeed. The enemy got his foot in the door of the church and some people were quick to completely dismiss certain ministries for their association with certain unnamed parties (Lets leave it that way?). I steered clear of some for a while, but the Lord didn't feel that way at all. He has many servants the enemy would love to dismiss, but many are gifts to the body. To esteem them lightly is to esteem the Lord lightly.
I started gobbling up testimonies of people who had died and seen Heaven and/or Hell (certainly extrabiblical). Some of them were very intriguing. Some were obvious deceptions given by the enemy to deceive. A few I couldn't tell either way. Some were so anointed an idiot could perceive it. Always strange how certain people are so against some of these!
What I do to discern if it doesn't strike me straightaway as being of God...
I worship the Lord and get in the Spirit. If you walk closely, you'll hear the voice of the Good Shepherd and He will NEVER let you get carried away. The voice of a stranger you won't follow. (If you don't get renewed, you're already in a position to be deceived.) Pray for discernment.
I compare what is said to the Word of God (What He has already established.) I can't tell you how many times the Lord upended my theology and I've had some very good teachers. You've got to be willing and open for God to do this. For all we know compared to many who aren't Spirit filled, we only know in a small part. The Word is "miles deep". As they say when you get older, you find out how little you really know...
The Holy Spirit builds upon what He has already established within. Some things are really of Him and you're not ready for it yet. It's all about your calling, so don't say something isn't of God just because you didn't get anything out of it.
Look at the fruit you're bearing when you listen to it (assuming you were led to it). You should be at peace. If you're trying to shoot them down, it's the enemy getting riled up. This often happens if the speaker is "threatening" a domain the enemy has in an area. God doesn't shoot His people full of holes and call it love. If something is amiss, you should have an inward witness (in peace) about something being off. Sometimes it will seem like the "wrong size screw in a hole". It won't be a tight fit.
Try to walk in what you're hearing. If it is instructive, you should be able to implement it. When you do, do it prayerfully and watch to see what fruit you start to bear. Do it with all your heart and look for peace.
It is possible to just be out of timing, so again, hold it up in prayer with the intent that you don't want to just be a hearer but a do'er. Step out if you have a sense of peace. "Try the spirit."
Bring it into the light with people you trust in the spirit. Do it when you're renewed and sharp. I like to do it at church when I know the person I'm speaking with is also renewed. Watch for the fruit of the conversation. Counsel in the heart is like deep waters. You can draw it out. Esteem the other person's anointing and get the reward Jesus spoke of.
Many times people have a valid testimony, and they "add" something to it with deductive reasoning. Roberts Liardon commented on this when he'd listen to people talk about their trips to Heaven. They see one thing and assume it had to be this way all of the time. (Big assumption!). This is why you ALWAYS judge in the Spirit what you hear. Anyone at any time can tack something on that isn't quite formed within you.
If you're still unsure, just put it on the shelf. Two years ago I found that I had faith to believe God for mysteries. I assembled every scripture I could find about mysteries, knowledge, revelation wisdom, understanding, doctrine, etc. and started declaring them out loud. I believe the Lord built this into my spirit where I would have a more discerning ear for some things He wanted me to know and lay hold of.
When I started coming across the answers the anointing really began to pour out and I knew I was receiving some answers to that prayer.
One huge thing though is to not have a judgmental spirit. This will completely obscure your "sight". Renounce it out loud and if you've judged anyone, renounce that too and bless the people you've judged. Remove the curse you've spoken over that person and speak blessing.
It' always good to get built up on the scriptures about the voice of the Lord, guidance, understanding, etc. and speak them over you. Agree with them and declare them as your inheritance. Of course you're coming as a child, not someone who got their Doctorate of Divinity. You're dependent on receiving from Him and light is your portion.
Recognize that when others (especially on the forum as a prime example) will exhibit the enemy when they cut people down. Although not always, it's often a good indicator that someone DOES have something from God when people start cutting it down with fleshy judgment. Discernment of spirits starts working and you can see them coming out of their holes to "shine the light" and "give guidance and counsel" (of the ungodly). The counsel of the ungodly and seat of the scornful -- never far apart from each other. The polar opposite is often the truth!
