If you’re a creative and having trouble picking a niche speed up how fast you make things.
This is probably the opposite of what you’re doing. Most of us, when we’re unsure of what to create we slow down to figure it out.
But if you’re a creative person you’re problem is too many ideas, not too few. And the more you stand still the more overwhelmed and limited you will feel by the idea of picking a single direction and giving up on all the other good ideas.
So instead speed up how fast you make stuff. The faster you make things the easier it’ll be to see what those things you make have in common and your niche will come out of the commonalities between what you make, not the stylistic limitations you set on yourself.