My main suggestion is to actually finish things, There is no shame in making a small project, like a 10 minute "almost-game", making something to a point where you can say, "Well, this is DONE!" is actually really cool, and very encouraging for next projects.
But the thing is, if you plan a really ambitious 1h game, with a progression system and branching paths, and you lose the will to develop after you get a 10 minute "almost-game", you will end up feeling like a failure, even if it ends up similar to what I described above.
So I guess what I'm trying to say is, don't go in over your head, start small, have fun, and when you feel like you can do something ambitious, let that flow and ride the wave.
Good luck!