If you are fighting a taller guy, I think you kind of have to reconcile yourself with the fact that you will probably take some shots as you attempt to get inside.
Definitely, stepping with a good jab or double jab helps, and make sure that you are ready to throw as soon as you get where you want to be. I make that mistake sometimes. I throw a double jab, get into the range where I want to be, and then pause between that action and the next, which would be unloading a combination. That lets the guy reassert his range.
Not that it CANT work, but be careful with any kind of diving or reaching punches on a taller guy. He has more time to see it coming, and you could set yourself up to getting timed with hard counters. When I am successful, it is because I am jabbing my way inside, and then throwing head and body combinations together without a break in the action.