I can only speak to what’s worked for me over the past few years and doing it on a full time basis (albiet with wildly varying degrees if financial comfiness).
I’m a big believer in small stuff first! There’s sooo much you learn about the drawing, writing, and the language of comics when you’ve started and finished several projects. You also get a ton of practice FINISHING things which, yes, does require practice a lot of the time.
I also really focused on the speed of my output so that now if I wanted to make my 1000-page epic it wouldn’t take me ten years but instead probably closer to two or three. But I also learned that a lot of my ideas starting out just... weren’t very interesting or good and if I wanted to do this full time with my magnum opus I don’t think it would’ve been possible for me if I started with it
The past decade also really taught me where i’m actually most comfortable in the process of creating comics and I don’t think I’d know myself as a creator as well if I had only done the one comic I remember thinking was my magnum opus when I was 18.
I have too many ideas and things I want to do and I’m going to die one day and not be able to get all of it out before that happens so I am just completely focused on working in a way that will allow me to efficiently get as much of it out of my brain and onto the paper as possible.