Hi, Peshang. I'm new here too.
I assume your digital art is drawing and painting. What software are you using? Do you have traditional training as well, and are transitioning to digital?
Is your sculpture real-world, or digital? What medium do you use (real world) or what software (digital)?
I'm traditionally trained, and have been "transitioning to digital" for the last ten years (yeah... really). I'm even now doing a massive comparison of software, for example, to see what works for me, and what doesn't, so I'd be interested in any input you've got on how different software packages are working for you.
See you around.
First off, Hi!
Let me see if I understand. Sequential art (including comic books and graphic novels) have two main somponents: the writing and the art. You say you've got the writing covered. Are you the writer, or are you a part of a team? Do you want to work on your own projects, or join someone elses?
My reason for asking is this: if you are the writer, the main concern you've got in being the artist in in matching the tone you've set in your head. This is a stylistic consideration that can take into account your lack of experience as an artist. In other words, you can make your inexperience in art a part of your style. Let the errors in your execution be a part of your style, and grow artistically as the series progresses. J. O'Barr, who wrote The Crow, worked this way. If you compare the beginning art in Issue 1 with the art in the final Issue 4, you'll see a massive development in his rendering and inking.
If you plan on working with a writing partner or as part of a team, you'll need to make sure that your artistic skills, whatever they currently are, will fit with the imagined final product. Make certain before you get too stuck in that your output is going to mesh with the vision of your team members. Be open to having your art be shaped by the input of others. Don't get defensive when suggestions are made to alter things, or when people need something else.
As a published author, I know the feeling of having someone else's art paired with your writing, and having it not be at all what you'd have suggested. As an artist, I insist on reading the manuscript before I do a cover or an illustration, and I also insist that the author has the approval on concepts and final product. As an author, I'd want that myself (but rarely get such a situation).
So tell us more about where you are, artistically, so we can give you more focused advice, if you'd like.
Good luck!