If you have perfectionist tendencies and you would like to have them not so much, consider playing around with the following tactics:

Break Early
If you're attempting something that requires regular adherence:

"I'm going to something every day for some time"
"I'm not going to whatever until whenever"
"I'm going to this every time I that"

Enjoy that starting momentum of a perfect streak, and then intentionally break early. 10-25% of the way in, or after 5-10 successes if it's not time-bounded. This relieves you of the pressure of a perfect streak, and you know you're capable of a perfect streak because that's what you did right at the beginning! You don't ever have to ditch this change just because you broke! You already broke!

Fail Quickly
If you're attempting something that requires the approval of an external figure:

"Someone will accept my offer for something"
"Person will support my plan to whatever"
"I'm going to qualify for that"

Brainstorm the steps you might take to help yourself succeed, and then intentionally fail quickly. Try your best to get it before you've prepared. This will give you valuable insight into your relative strengths and weaknesses in the endeavor. It will also show you that just as you were imperfect in your unprepared first attempt, you will also be imperfect in your prepared final attempt, the one where you succeed. Because you're human don'tcha know.

Think Abundantly
If you're attempting something with an attitude of perfectionism about you:

"Something must happen some particular way"
"Whatever must be done by whenever"
"It's either this or it's that"

Snap out of it! Think abundantly: what assumptions did you make that gave you such a rigid success criteria? What would happen if you expanded your frame of success or rotated your frame of success or turned your frame of success inside out? What would happen if you dropped your frame of success altogether, and it fell on the floor and shattered? What then?

Countless shards at your feet, all shimmering in the light streaming in through the window. A beauty that scoffs at all attempts to capture it. A hidden knowledge that was there all along, finally exposed to you. You will forget. You will remember.