1) God says “Yes.”
2) God says, “No, My grace is sufficient for you.” (And sometimes a “no” is actually a blessing in disguise.)
3) God has strengthened your conviction that this is indeed the way you are to continue praying, and you need to persist in prayer until it happens.
4) God has purified your desires through the trial and the waiting, and He has shown you how to change your request to be more in line with His Will. Or . . .
5) You realize that you have made an idol out of the request and the answer that you want.
And if that has happened, I think it is wise to put the prayer request aside, for a time at least. When we learn that we have been so focused on a request or on the pursuit of the answer that we want - to the point that we have lost our focus on God, lost our confidence in God, and have caused ourselves emotional distress - then we need to confess it and to fully hand the request over to Him to do with as He pleases. And this, when we can do nothing else about this request, is the time to praise Him. And to keep praising Him - until we have Him so clearly in focus and at the forefront of our minds that our desire to get what we want pales in comparison to His glory and His love.
(Also, if it seems as though God is not answering your prayer, ask yourself if there is anything that you should be doing or not doing. Sometimes, we pray “lazy prayers.” We ask God to do something for us while ignoring the resources and wisdom He gave us to do it ourselves, such as praying that God gives us a healthy body when we won't exercise or eat right. Or we pray prayers from the wrong angle, and we need to slightly shift what we are asking for. Instead of praying, “Lord, change my spouse,” it would be far more effective to pray, “Lord, help me see what I can do/think/change to make this marriage better.” Sometimes, to get our prayers answered, it takes tweaking them a little or praying that God opens our eyes to the answer that is already there.)
In the end, I have to wonder if God doesn’t always give us everything we ask for simply so none of us can feel like we have an inside track to God and so that we put away our “pat” answers about faith and God and life. So that we can never shake our heads at others in condescending pity when their prayers aren’t answered the way they want, thinking, Poor things. If only they prayed like me or had my strong faith. And so that we remember that none of us can really understand or control God. (And isn’t this exactly what most of us get hung up on in a crisis of faith? But a god that can really be totally understood or controlled by us is not really God at all.)
Summing it all up, when it comes to prayer and faith, what we should want more than anything is to get to the place where we can take His hand and walk forward into the darkness in faith. Faith in Him! Because even if we don’t get what we want, we know that He is a good, loving Father who will work all things for good!