Firstly come up with a “Roadmap” of what you want. Start off with your concept, what do you want the game to be?
Take it baby steps at a time, focus on planning first and figuring out what you want in your game, once this is done I would suggest focus on making your core gameplay concept before anything, i.e your scripting stuff.
Once this is done to the point that you’d like, this is where you can implement your other elements. Is your game a story game? Level based? Is there a progression system? This is the time to start coming up with and implementing this into your roadmap.
Once this is done I would start modeling and creating your game (Modeling and misc. scripting wise). This is where you bring your game from a simple concept to a game.
After this is done its time for your final testing (if you decide to have testers) and polishing the game. Tidy up the map a little bit, add your easter eggs, add those tiny details.
After this is done you’re set to release.