Hi, i would recommend you to try out some other tools to work with. Try using charcoal and sharpen it correct way (doing it with sandpaper), you can achive better line quality. You should also try all sorts of grips, they will help you achieve a lot of diffrent line quality. Spend more time on realising what is comfortable for you, bigger format of paper or smaller. Also i would recommend that you work from your shoulder not from wrist that will help to get more action in to those drawings!
Have a nice day!