That depends on how much you know about analog. If you already know the basics, such as transistors equations, calculating operation points, gm, rds, and all those equations then you can start designing amplifiers right away, starting with Two-Stage amplifiers and evolving to more complicated strutures as your experience increases. Always guide yourself with a book such as the one written by Razavi.Pay attention to details, in analog everything matters.If your knowledge is very limited, you should start by even simpler things such as common source amplifiers. Razavi's book can help you with that too.
Anyway, learning amplifier circuits is the best way to begin working in analog since those are the basic building blocks for everything.
Mastering analog design isn't easy and takes some time. It's very mathematical so learn and understand the equations. It's easier to do it if you practice as you learn.
Good luck