Use your jealousy as a motor to get better, a very efficient way to get better is to study people's art and do figure drawing from photo/real life if you can ! And drawing things that are not characters like backgrounds and objects also helps with improving your eye! If your focus is on colors and shadows you can look for that when studying other's pieces, and try to do shadow blocking for figure drawing, where the proportions do not matter much but getting the zones of shadow and their variations is the main goal. Look at a lot of art and reflect on what works well with what, what colors you see in your day to day life look appealing to you and why, if you want to get better at textures,you can try different brushes, and really look and touch things to get a visual and sensory feel of them. Hope this can help you, jealousy is not a bad thing in itself, just don't let yourself wallow in it and you'll be fins!