I have heard jabs called the 'queen of boxing'. Most judges in amateur fighting look for the number of punches thrown and the jab becomes critical. Ask your coach if you can do jab drills with another more experienced fighter in the ring. That should put some challenge into your skill and expose any flaws in your delivery. Also a good way to polish up your slips and defense. Your partner can critique you between rounds and maybe give you some pointers. We use to refer to this a 'drills'. It was a step up from the heavy bag, and before full sparring.