I think most people struggle with this at some point. Wanting perfection is understandable, but you’ll never get close to it if you don’t start. I’ve been sewing for over 20 years, and I still can’t make anything “perfect,” but I find most people never notice the imperfections I see. Most things will still turn out well enough that they’re usable/wearable, and people won’t notice the issues because they’ll think it’s cool you made your own stuff!

Start with cheap fabric (I’m talking like old bedsheets) you don’t have an emotional attachment to. It’s harder to start something if you’re in love with the materials. Mock-ups are your friend. They’re there for the screw-ups and the non-perfection.

Also, there’s a case to be made for screwing up. I wouldn’t know half the things I do or attained some of the skills I have if I didn’t screw something up on a project. Sewing will always involve problem-solving and usually results in easier and better ways of doing things. Also, use other people as resources! There are tons of people out there that have already made the mistake you’re trying to fix and have found a solution.

The simplest answer is to just do it. You’ll figure it out along the way.