I can read my wife's mind. Not all the time. But in a very specific set of circumstances, she doesn't have to finish speaking because I know exactly what she is thinking. See, she says, "Honey..." which is not unusual in terms of addressing me. But there are times when she says it that I know she wants ice cream. Every time she wants ice cream, I can't explain it, but I know she does. I don't know if it is the way she calls me or the expression on her face but I can tell she wants ice cream. I can tell exactly what she is asking even though she never actually asks. Normally she just confirms my guess with a sheepish grin and a big nod.
In Genesis 18-19, we see an example of God doing the same kind of thing with Abraham. God had let Abraham know of his intention to destroy Sodom and Gomorrah and Abraham began questioning God, concerned that God would destroy the righteous people along with the unrighteous. Abraham began negotiating with God to spare the city if so many righteous people could be found within it, starting with 50 and working his way down to 10. Now Abraham probably was actually concerned about righteous people being killed alongside the unrighteous, but he was probably mostly concerned about his nephew Lot and Lot's family, who had recently moved to Sodom. Abraham never specifically mentioned Lot's name but after God had sent angels to rescue Lot and then destroyed the city, the scriptures state, "So it was, when God destroyed the cities of the plain, He remembered Abraham and brought Lot out of the middle of the upheaval when He demolished the cities where Lot had lived" (Genesis 19:29, HCSB). Even though Abraham never specifically mentioned Lot, God knew exactly what Abraham was asking. The New Testament talks about the same mysterious dynamic this way: "In the same way the Spirit also joins to help in our weakness, because we do not know what to pray for as we should, but the Spirit Himself intercedes for us with unspoken groanings" (Romans 8:26, HCSB).
If you are in a difficult situation and you don't know how to pray or what to pray for, just pour your heart out to God. God knows exactly what you mean and exactly what you need. Trust him and, like Abraham, God will know what you're really asking.