The anatomy of your characters is a bit off. The arms and legs seem to be more like sticks than fabric, over skin, over muscles, over bone. I'd recommend studying things like what muscles make up the arm, what forms do they have, etc. I think it could really propel your art to the next level.
Something a bit easier to tackle would be your line efficiency. Your lines are very messy, which disguises the forms of what you're painting, and generally makes it seem less professional. Practicing line efficiency is a bit tedious, but can pay off big. Try filling a canvas in photoshop with little things like straight lines, circles, curves, little zigzags or whatever shapes fit your fancy. Then go over each item about 5-10 times.
Great work! Can't wait to see more ^^