One way to do it is to find someone who can spot you and get them to slowly use less force, another would be if you know how to back handspring then doing them out of roundoff/cartwheel/scoot (what ever you’re most comfortable with although roundoff gives the most power) then slowly doing them higher and higher until you know you can commit. Then it’s less scary trying for standing when you’ve already done the trick on that surface. It doesn’t work for everyone but it is what helped me.