Danimal i suggest start by making components, test them first, test your abilities to do stuff.. if youre a knob like me, who has pretty much no bg in education, programming, high maths, skills, money, then i suggest you try out your luck by training to make what your dream game would need..
Imagine, how would you start to make a game, what game needs in order to function?
Main menu?
What kind of options would you want user to change? How do i change settings in game and make changes on the user pc accordingly.
Networking? How to create multiplayer game? Lobby system? Ranking system? How to calculate stuff in order to assign rank based on properties?
Controls? What controls? How to create control bindings for user to change on the fly?
How to save game? Load game? Persistent user data.
After you got the hang of how to use the godot tool, to solve these essential problems, then you would start exploring the game mechanics, because many times you will find yourself re-writing whole code base because you structured the game code in such way that it needs to be re-written in order for something to work as you want it to work.
Examples would be inventory system, minecraft mechanics for placing blocks, generating procedural worlds etc..
After you got the hang of how to create the things you want in your game, you could start looking at the visual/art style aspect. Learning the tools like Blender and other tools to create the things you want
And then you get it all together and you have yourself a game.
This is how i see and how i approach my workflow.
Its important that you record your doings, create simple example projects that deals with certain problem with a solution. Clean up that code, for later use. Otherwise when you get to the point of implementing some feature and looking back you wont remember how things worked unless you have left yourself clues.
OFc the most important is having a clear vision of what you want and you have to know/see (minds eye) how the game should look/feel/play. Without that youre like a blind man at an orgy.
Working in teams could increase productivity and thus getting to your result faster. But working alone you have to divide your time and focus on tasks you can achieve and know how to achieve. Fly fishing is not productive, and then you will lose motivation and energy to move forward and will get stuck in a vicious loop of, Im a failure, nobody loves me, die.
As for software, there was a thread
https://godotforums.org/d/28944-free-software-for-content-creation