Have it in mind. Allow yourself to fail. Free from too much expectation. And don’t be angry on yourself. Cause this doesn’t help at all.
You shouldn’t have expectation at all if you do something first time. But you have. This is the problem. Falsehood. Not problem you solving is a problem. But your untrue beliefs.
Try another solution. And remember, second time is better. But also isn’t best. So don’t be angry if don’t work at all, too.
Don’t bash, over think. Keep it simple, stupid. If you start to feel stressed, take a break. Even when deadline is coming. Your mind finds new ideas in diffuse mode better than you can. No matter how you would try.