^ Pretty much these things are my two go-to pieces of advice when starting out!
Starting small is valuable because it's more feasible to finish a short project than a long project (typically. I'm sure there are exceptions) and having a finished project is super important! At the very least, it's important to be able to get practice on how to end a comic- if you start several long projects that you never get around to finishing, you still get a lot of good practice for making comics in general, but that practice is mostly concentrated at the beginning and middle of the story. Writing and executing endings is its whole own separate skill that needs to be developed too~
The other thing is having a finished project is a really nice feeling and morale boost for a lot of people! There's something really nice about being able to look at a complete thing you made and be like "Way to go me, I did it! The whole thing!" and those kinds of feelings can be used as momentum when moving into the next project!
My personal experience with starting out on Tapas: I've been making comics my whole life pretty much, but I was super guilty of starting a lot of stories but never finishing anything xD throughout elementary and middle school I probably made at least 20 fan comics for different series that I liked (Pokemon, Digimon, Naruto, etc.) and would always get like 5 pages in then drop it for something else. In highscool I started working on an original project, but it was way too long. Basically inspired by shonen anime, so it had a huge cast and many arcs and probably would have been like 100+ chapters long xD I continued to kinda-sorta work on that for yearsssss. But again, never got further than chapter 2 in drawing form (got up through like chapter 8 in novel form! The comic version suffered numerous re-starts).
Soooo when I finally came to Tapas and wanted to try something else out, I decided to write a short-ish story that would only be ~+/- 50 pages long. Which is still a lot, as I'm learning now a year later and just finally almost done, but it was still a reasonable starting project imo with my past experiences xD I've also worked on a short collab comic with a few other creators, and drawn a separate 10-page short story in that time too! Those finished projects were super refreshing and breaks from my main comic and had that morale boosting effect!