Design
I adapt my process to the kind of game I am making and what my role in the project is.
On solo projects, I visually note down everything that feels right to add. These notes usually include the art for the game's visual style, game design problems to solve, UI styles, programming related stuff etc.
A 'blue sky phase' where I tend to ignore limits and just focus on concepting and brainstorming. What would be a visually interesting thing to see? Do I want an explosion of colours or just some in the right area? What themes am I potraying?
How will the player do what?
I wanted to make a game about playing piano on your keyboard. The player would go around eloquently clicking different keys with purpose and intention.
All this would happen through spaceships of course!