When I have write a proof and I don't see how to start. I look at what I supposed to be proving

 and see if it make sence. If it does, I ask myself why. Sometimes this helps me to what the reason

 in proof might be. If all else fails, I just start write down everything I know based on the diagram an

 the given statement.By brainstorming like this, I can usually figure out the state of the proof.You

 can even write each thing on a separate piece of paper arrange the pieces of paper like a

 flowchart.