The easiest way to get clients to your design business is to make great designs.

Onur Cobanli ཡིས་འགྲེལ་བཤད་བརྗོད་པ།
It may sound obvious but it is not; because like in any business, you have many ways and paths that you could take; you can take the quality path or you can take the quantity path. When you are a young design business the quantity path maybe a better initial choice as you would have opportunity to work with a lot of clients, and to work on different projects which could help you understand whether you are inclined toward a specialization or if you like certain type of jobs, furthermore doing more tasks will provide you with more experience. However, once you have a level of experience, I strongly recommend that you start designing for quality; in general people will judge your design business with your best and worst work; start getting rid of your worst works from your portfolio, and focus on trying to get more best works; work on getting more great designs, as if you have several great designs, and no bad designs, you will be able to work with really good clients that respect your design qualities, and renumerate accordingly.