Really? You can choose to believe something? I'm really not sure I can. If you really think that you can, try an experiment like this:
1. Look closely at something familiar--maybe your car or your house, for example. Identify what color it is, or what colors predominate.
2. Now turn the other way so that you can't see it. Choose to believe that it's a different color.
3. Turn at look at it again. Are you surprised by what you see?
In my personal experience practicing self awareness has helped with this. I understand that there are factors outside of our control, but what goes on within us can be controlled to some extent with effort and time.
We have a subjective impression of control, but that too is only the result of physics.
On a serious note, Sam Harriss essay on free will is a good read, nihilism and existentialism too.
A point I'd like to make is that surrendering and accepting to things you don't control can bring you short term peace but will crush your long term peace. I personally don't care if I have or don't have free will, there are things about myself and the world around me that I cannot control but will never stop trying to fight against it. Hurting people, for one. I think that's my definition of free will.
Someone else made a point that free will could be similar to the god of the gaps theory, where free will is in the gaps.