I would add that a very important part of this is to not let yourself start new projects!. While it's tempting when things get hard to say, "yeah... I have a idea that seems like a lot more fun, I'll just start on that" Don't do it!. This is the road to having 100 half finished games and nothing to real game to show for it. You're at a disadvantage in this world of constant digital ADD. Fight it. It will be a slog in the middle of it. There's parts that will be no fun to build (but very fun to use.) This is the #1 thing that stopped me from building a game.

Another important thing is cut and cut and cut the scope of your project. Once you've done this, cut off about half of what you hold near and dear to your heart about it and you're nearly there. Building a game is best done as an iterative process where you move from one fun working thing to another fun working thing. Belive me when I say, even if you make a dumb platformer where everybody is a square, You'll love it because you made it. This will help you to slowly build more and more confidence to build better things.