When you pray, how much time do you spend praying for yourself? Your immediate family? People and situations you don’t have a vested interest in? What sort of expectations do you have when you pray? What do you think is going to happen?
Despite how many of us typically pray, prayer is not an indulgence in narcissistic self reflection. Nor it is a chance to remind God about doctrine.
Instead, it is an opportunity to worship our Creator and Savior. It is an opportunity to intercede on behalf of those in need, which may well include the one praying, but ought at least as often to be about someone else altogether. Despite what many of us have been taught, we pray to do more than just change our thinking.
We pray because we believe doing so causes the power of God to flow through us on its way to meet the need we have brought before God. Don’t listen to those who say this is to be metaphorically or mythologically representative of some other reality.
Instead, put your prayer life to the test. The test of a prayer is its efficacy – did what was intended come to pass? In everyday language, did it work? Did God do what you asked God to do? Richard Foster provides us with a nice analogy:
If we turn on our television set and it does not work, we do not declare that there are no such things as electronic frequencies in the air or on the cable. We assume something is wrong, something we can find and correct. We check the plug, switch, circuitry until we discover what is blocking the flow of this mysterious energy that transmits pictures. We know the problem has been found and fixed by seeing whether the TV works. It is the same with prayer. We can determine if we are praying correctly if the requests come to pass. If not, we look for the “block”; perhaps we are praying wrongly, perhaps something within us needs changing, perhaps there are new principles of prayer to be learned, perhaps patience and persistence are needed. We listen, we make the necessary adjustments, and try again. We can know that our prayers are being answered as surely as we can know that the television set is working. 
This is where I should add on a bunch of disclaimers about how we don’t always get the answer we want, we don’t always pray according to God’s unchanging will, etc.
But I’m not going to do it. If you are praying for something and God isn’t going to do it, then at some point, God may tell you this and release you from it. Or it won’t happen and then you will know, like when David prayed for the baby Bathsheba bore, he prayed until the child died, then he stopped. Jesus taught us to pray relentlessly, keep asking for what we and others need, like a child asking a loving parent for some food.
You see, those who say we can’t change God’s will with our prayers have it wrong. What God has willed is that we pray. It is God’s will that we bring our petitions before him and receive divine blessings to meet those needs.
I like Foster’s analogy – we should pray expecting an answer like we click the remote expecting the TV to light up. It would also be good if we prayed at least as often as we turned on the TV, but that’s another post…
 Richard J. Foster, Celebration of Discipline: The Path to Spiritual Growth, 20th Anniversary edition (San Francisco: Harper Collins, 1998), p. 38.