Fellow artist here! I love the colors! I second brushing up on your anatomy, but I also wanted to recommend plastic artist models. Like gray scale action figures of poeple, but proportionly correct. I use them all the time. Get a stick for a prop sword and your good to go. Really helps me rough out a pose and make sure the prop/object is being handled naturally.
Which brings me to my next point, pose. Even standing still like this you can give your charters a sense of self and personality. Look for a dynamic action in the hands. Figure out which leg is taking weight and which isn't.
Have you ever spotted one of your friends from some distance away? You couldn't see their face but you knew it was them becuase of how they were standing, how they carried themselves. Same idea.
One of the things that helped me was gesture drawings, no details just motion. I would grab a sketch book and head to a park with lots of poeple and free sketch. Also get some books on animation! Sorry I have written a novel here but I LOVE art and have been painting my whole life! Keep going! I can see the skill in your work. Hell your probably better at clothing than I am! (I have to get mad reference for clothing, especially shoes.)