- Use git.
- Make offsite backups.
- Learn about common software architecture patterns.
- Use git. I am serious about this.
- Learn how to read API documentation, and the documentation for your frameworks/libraries/engines (Godot, in this case) in particular.
- Don't be afraid of slapping some shitty placeholder assets into your game early on - you can make them good later.
- Think ahead about what your code needs to do in the future, and how you can make it flexible enough for accomodating these things.
- Use git. Absolutely use git. Always use git. You will regret not using git.
A lot of these are skills you'll build over time - you don't have to go read five books about architecture before you can start writing your first line of code, of course. Just tuck these things in the back of your mind and build your skills there over time.
(Except for off-site backups and git. Those protect you from losing all of your work, and you should set them up right now if you haven't already.)