Hello there! I highly recommend focusing more on drawing! The key to a good illustration is solid drawing skills. Focus on studying anatomy, and by anatomy, I don't mean muscles, but rather the construction of the human figure. Learn gesture drawing to create more dynamic poses, and learn how to construct the body using simple forms to work out proportions and perspective. Learning these skills will give you a solid foundation for your characters and help them look more dynamic rather than stiff, hehe. If you have the opportunity, sign up for ArtWod and follow the Beginner Roadmap, then move on to the Human Figure Roadmap. Or try to get "Figure Drawing Design and Invention" by Michael Hampton. Hope this helps, and keep it up!