You have a bad habit of making one arm shorter/longer than the other when you draw a bending arm. It's a common mistake, so there's no need to worry, but I recommend you pay attention to the length of both next time you draw. Also, I noticed that you tend to make one eyeball a bit more misshapen than the other. Try to make them a bit more circular/oval-shaped. These are common mistakes, so you don't need to worry if you don't end up fixing them, but the small steps count.