"Teach me to do thy will; For thou art my God: Thy Spirit is good; Lead me in the land of uprightness." (ASV)
God answers the prayers of His people. Of course, this is not to say that He will grant you anything you ask for. He's no magic genie after all. No, God has His own plans for us, and He knows much better than we do what will be good for us. But we can be assured that He hears us when we pray. "For what great nation is there that has a god so near to it as is the LORD our God whenever we call on Him?" (Deuteronomy 4:7 ASV)
There are some things we can pray for that we know are always in God's will. Of course, these prayers can often bring about more than we were hoping for. Often Christians have prayed that God would use them or show them what they should do with their lives, and found themselves used in a way that they never would have expected! While this can be scary when it takes us out of our comfort zones, we know that God will never put us in any place where He does not go with us. "And he said, My presence shall go with thee, and I will give thee rest." (Exodus 33:14 ASV)
Another request that we can (and should) make to God is that He help us to keep His commandments. Apart from Him, we are powerless to overcome the sinful nature we are born into. Fortunately, we know that it is God's will that His people remain righteous, so we know that He will help us to overcome the trials and temptations we struggle against all our lives. Does this mean we will be perfect? No! Far from it actually, because we are still human and will not be perfected until we ascend into heaven. What it does mean is that God will help us become closer to righteousness with every passing day.