May I suggest that you try being a bit afrid, at least, of getting hit? If you aren't you are probably a lunatic: getting hit hurts, causes damage to your body, and scores points for your opponent. So you try to avoid it but don't let it ruin you when it happens.
Plus, defense- the art of avoiding punches- might be the key to helping you land more punches against taller foes with reach advantages. As you come forward he can pepper you with punches and if getting hit it is hard to punch back; when you get a chance to punch he is most likely concentrating on defense and hard to hit. Which only proves an old saying: the easiest and most effective time to hit him is when he is trying to hit you.
Every single punch you or an opponent can throw leaves an opening, a vulnerable area that can be targeted...IF you make the punch miss you instead of eating it or taking it on the gloves (you need them to punch back!) You should make it a point to make him lead and it should be easy: you are shorter and coming forward so he'll want to get off first with his jab, right? Slip the jab so it goes over your right shoulder and throw a straight right to the heart and pull inside. He throws a jab-right hand catch the jab in your right glove slip outside the right and hook the body.
The possibilities are infinite, or at least numerous beyond my patience with typing, but do you see the idea? Create your offensive, punching chances with your defense. Try crouching a bit, your weight favoring your back foot, leaning a bit left (away from his right) and stay well to your right as you advance. This will make him (A) more apt to drop the left when he jabs and (B) reach with his right. You'll get hit less and will find it much easier to land good punches off of his misses.