hmmmmmmmmmmmmmmm i'm bad with advice about art bc i don't want people to take it the wrong way, and i think that just drawing and using references as often as possible can help improve, idk

pay attention to proportions and figure out if your figure/oc is balanced physically (if your doing grounded poses). references are good for help but also look at other art and/or if you have been working for a while take your mind onto something else to refresh your mind and you can find any mistakes. try out new and different things, challenge yourself, draw what's on your mind out of pure bordom because you can always be creative. but another thing in mind, be brave not cocky.