Let your project be bad for a while. Most good things pass through a bad phase on the way.

Every unfinished thing goes through a stretch where it is clearly worse than the idea in your head. That stage is not a verdict, it is a construction site. People who abandon projects usually do it right there, mistaking an ordinary phase for proof the whole thing was wrong. Work that eventually turns out well almost always looked bad for a while first.

When you hit the ugly middle, name it out loud as the ugly middle and keep going for one more session. Do the next small task rather than reassessing the whole project. Reassessment belongs at the end, when there is something to judge.