First you have to make space in your life for it. You need long blocks of time for deep work.
The first idea you pick is unlikely to work, so pick something and start moving. Many of the best products come out of working on something else.
When building, optimize for speed. Try to get something out in the world as quickly as possible and iterate from there.
Pick a tech stack you're familiar with, that you'll be fastest in.
Try to spend half your time on marketing/sales, even if you hate it.
The most important skill you can have is resiliance. Not giving up is the best path to success. This is hard because there is so much uncertainty in this career path.
It's worth it! The autonomy and freedom are unmatched by any other career.