Start small, learn from your mistakes. Nothing more disheartening than getting half away through a big project and realising that there's a much better way to do it (or that you've rendered it all wrong).
Small, disposable projects that you don't care to much about and don't end up investing to much in are a good way to start. You'll learn and get some confidence from the ones that work and minimise your losses from the ones that fail. Only when you've got some experience do you want to get into something bigger.
Don't forget to play other peoples games and see what you can learn from their mistakes.
Try joining a jam. Folk in jams seem more open to giving feedback than the general itch.io community.