Good advice from everyone. I might add that a big part of striking is learning to read your opponent. Learn from exchanges. What do they do when I leg kick, how do they defend my jab, or other offensive moves.
You have to know what your opponent is going to do (as best you can) before you move. Then you can apply your combos.
For instance if I see my opponent is covering on every jab, my next jab I'll drop down to the body. Change levels, see how they react. Do they drop the guard, do they counter? What are their reactions so you can predict them, and then come up with a strategy with that info included.
Point is unlike mitts, live sparring involves a thinking moving person, you have to read and adapt to that person (this applies to any type of fighting not just striking).
I can say I see a lot of fighter who go in and just throw the combos they know, with no attention being paid to who they are throwing them against.
Undefeated in all of Asia!