Tell yourself there is not going to be a perfect time to get started, and that you don't have to be perfect in your performance. Compromise and start immediately and rough out task, and then build upon it. No one is standing upon your shoulder demanding that you make no mistakes.
This is a problem I have. Because I spent so much of my life trying to prove my value and worth and to elevate my family's image, I became a perfectionist. It's funny, but trying to always be perfect often results in your not getting much of anything done.
The pressure that perfectionists put on themselves is so intense that can't possibly be perfect at all the things set out to do; as a result, they get stuck. Believe me, I know. I am constantly telling myself to ease up, and to just take each task step by step, without fear that someone will criticize my work.
This perfectionism was the main impediment to my own efforts to make good decisions to better my life. A lot of times we make things more difficult for ourselves by placing this sort of undue pressure on ourselves. .
You are far more likely to succeed if you work to please yourself, without feeling pressured to meet the standards of others.