How? In the freelance developer space you're either competing with people in developing countries who work for peanuts, or your potential clients have have the money to throw at high quality work which means you're competing with the top 1-5% of freelance developers.
There are plenty of companies that just want results. They don't want to deal with the hassle of online developers they don't and can't trust. Start as a consultant and get a great reputation and you'll have more work than you want. Also get advice on the best practices. It's easy to get locked into contracts that are just not worth doing.
You should take a look at Toptal, I use it for just this, working around 20 extra hours a week. Can't give out my rate there, but it's fair.
Easy to get gigs once your in, the clients I've worked with have been good. Very little mental overhead since they handle invoicing, getting customers etc.
By finding a niche and looking for work in that niche. I picked NLP in the financial space and have been able to find work within a couple weeks every time I look. If you search for freelancing threads here on HN you can find some great info on getting freelance work.
This sounds like something that requires a masters degree. How did you manage to prove that you were knowledgeable/skilled in NLP when you got your first job in that space?
Full time job is for a consulting company. Got brought on for some greenfield work that happened to be in the space. Got to learn on the job. Leveraged that experience to land freelancing clients.
Sounds reductive but I’ve had good success with this when looking for additional income.
Probably the easiest and most likely to work path if you are already a developer.