It might be helpful to work on tasks or games where the goal or scoring rubric is based on generating responses quickly, with much less emphasis on correctly.
You could play games like "How many words can we come up with in 1 minute that use only the letters from 'perfectionism' ( or 'paralyzed' or 'exasperate')." Incorrect responses have no penalty, 5 points gained for each response (correct or not) above a certain threshold, with one extra point earned for each correct response.
Anything that bases the reward on taking the chance rather than getting it perfect would be a step in the right direction.
HTH.
