I am going to assume you want to build an actual business with employees, and not just start out as a freelancer.
My first tip would be: read “Traction” by Gino Wickman. The system outlined in the book (EOS: the Entrepreneurial Operating System) is one of the best ways of structuring a growing business.
Read it and treat your new business as if it was bigger than it is right now. Establish a vision. Document your processes. Create accountability and start forming habits, even before you hire anyone.
Michael Gerber in his book “E-Myth: Revisited” (yes, you should read that one, too) says you should treat your own business as if it’s a franchise – even if you have no intention of it never becoming a franchise.
The reason for this is that by systematizing all your processes (to the extent that any new person can be trained up ASAP) you retain the company’s identity and your vision, even after you hire a bunch of people.
A lot of entrepreneurs “just start” and end up with a business they’re not happy with. That they don’t recognize anymore. The truth is, practically speaking, of course you should see if your idea is viable, first. But as soon as you know you’ve got something, put in the work.
As a new business owner, work ON your business, not just IN your business, from the start.