According to Matt. 6:8, God knows what we need even before we ask. And here is a wonderful promise:
Isaiah 65:24 KJV
And it shall come to pass, that before they call, I will answer; and while they are yet speaking, I will hear.
But there are some conditions to having our prayers answered. God cannot answer every prayer. Consider the following:
Proverbs 15:8 KJV
The sacrifice of the wicked is an abomination to the Lord : but the prayer of the upright is his delight.
And:
Proverbs 28:9 KJV
He that turneth away his ear from hearing the law, even his prayer shall be abomination.
While nobody's perfect, what these texts are telling us is that God cannot answer the prayers of those in willful rebellion against him. I imagine someone in the act of robbing a bank, praying that the alarm won't go off, or that the getaway car has plenty of gas! Obviously God is not going to cooperate with prayers like that!
May God grant you the desires of your heart, is my prayer for you.
I want to add: if we pray for something that is not good for us God will not answer that prayer.