This technique reduces the procrastination that typically results from perfectionism. Suppose you must find references for a term paper and also study for an exam. Set time limits. If you stick to your time limits, you won't spend the entire day searching for elusive references, nor try to study late at night when you are too tired to be effective. Learn how to deal with criticism.
Perfectionists often view criticism as a personal attack, responding to it defensively.
Concentrate on being more objective about the criticism, and about yourself. If someone criticizes you for making a mistake, acknowledge the mistake and assert your right to make mistakes. Remind that person and yourself that if you stop making mistakes, you also stop learning and growing. Once you no longer buy into the fallacy that humans must be perfect to be worthwhile, you won't feel so angry or defensive when you make a mistake. Criticism will then seem like a natural thing from which to learn, rather than something to be avoided at all costs.