I believe everyone have their own process to develop their game and there's no one perfect way to do so.
Depending on what you're doing and whether you're doing it solo would entail different method but based on your post, I'd assume this is your first time attempting to work an actual project. The most important aspect would be the basic premises of your game. Your story (if there's any) would be the main catalyst in what you'll require to make the game happen. Art, music and maps all would depend on your story. You wouldn't care about having a snow tileset if your story takes place exclusively in a tropical island, right? You wouldn't use upbeat music if the tone of your story is constantly dreadful, huh?
That's it; story and premises. If you don't have anything tangible yet when it comes to those two items then sit down and think through what you're trying to do. Don't attempt to make a 50 hours game as your first project. Start small, try to craft a small self contained story of one hour or two and see how it works out. Once you start seriously working on a project, you will develop your own practice on what to work with at first and what comes next.
Personally, I am currently working on a project that is highly a Visual Novel but I still choose RPG Maker MV to make the game (I considered Ren'py as well). My thought process about this choice made MV an obvious choice due to how I can easily craft small map to give the player more choice without relying exclusively on menu-type of choices. I had a general idea of my story but I was against writing everything down, instead I have a sort of diagram where the story progression is described very briefly and it will be expanded once I finish making the resources for the game. Meanwhile, there's some specific things that I need for my project and I contracted someone to create the specific resource. Meaning while I am working on one aspect of the game, someone else is paid to work on another aspect that I might not be skilled enough to tackle.
All in all, learn to use the tool first and you'll figure out yourself how to work flow.