Getting Started..

How. I have a yard of 1/2" foam and I've been saying I'd start working on the head base for my fursuit project and even after making two different heads in the past, I'm too scared to jump right into the project.
I'm afraid I'll mess up somewhere and waste foam..

Any techniques/tips before I start? This costume's gonna be of my fursona, so that's part of why I'm so worried about starting..I just wanna make sure I make this costume the best I possibly can even though I know I can remake it in the future if I'd like to..

Anyone else have a sort of anxiety before getting started? //fails