Win five clients. Then win five more.
The first five prove someone will pay you. The next five prove it was not a fluke.
If you are starting, this is the work. If you already have clients, the next batch is still five. Same method. The Guild treats both as one job: make winning clients a thing you can do again.
There is nothing new to learn here, other than the discipline of doing it in batches of five. A burst of luck is not a business. Five, then five more, is.
The first-business method, in full, is at First Business Kit. First Business Kit