I think that self promotion should be done by telling people about your skill and how good you are. You can give discounts or charge very low in the beginning to create awareness in the public, because people from my country patronize cheap servives as long as it is a reliable one. You need to advertise yourself, or get someone to manage you. That person will be the one to look for clients for you. You might be good or an expert in your skill but you might not be a good promoter.
True, prioritize learning when you're starting our and genuinely help people solve problems with your skill. Indeed, having a skill is not all, it's a start, but you need to know how to market those skills and get clients, and not just any clients, but clients that pay you well for your time and value.
One of those ways is to join a community while learning, and interact in those communities. You can join job boards like Upwork, join professional platforms like LinkedIn, where people showcase their skills and get clients.
Try connecting and cold DM people on those platforms, connect professionally and learn to support people too, because in supporting people's journey, they know you, and they also recommend you, that's how referrals come.
And be visible, and show up with solutions to peoples problems, any platform you choose, LinkedIn, Facebook, Twitter, be visible, don't be a post and ghost somebody, always show up. Be active, be around, let people see you, let your profile be popping.
Learn copywriting, learn how to use words to market your skills, learn basic marketing and positioning skills, position yourself properly. Always upskill to be one step ahead of others that are in your field.
And don't be ashamed to market yourself, some people are ashamed, go out there and tell people what you do. When you want to introduce yourself, when you say your name, you say your skills too.
Let it keep occurring to people that, you are, for example, XYZ, a software developer, before you start saying anything. Always put yourself out there. A good skill in a box is of no use to the person that learned the skill and somebody that needs the service.
Go out there and help solve someone's problems with your skills.