Use Bruce Lee’s 5 ways of attack:
Single Direct Attack – e.g. Jab
Combination Attack – E.g. Jab, cross, inside leg kick
Attack by Drawing – Using a lean-back, by using feeler punches to ‘draw out’ a defensive opponent who is waiting for you to throw first
Progressive Indirect Attack – gauge and read your opponent e.g. how he reacts to a jab
Hand Immobilisation – Manipulate the hands if necessary (this works best for ground and pound). See hand trapping techniques of JKD for examples. This is least applicable of the 5 principles to boxing but still good to read about.
Jab with Head off Centre Line
Especially important if you’re short. I like to move my head down and forwards to my right as I jab. Don’t leave your head there in kickboxing tho, you can eat a kick to the head.

Jab with head to the side. Turn thumb down at the end of the punch. You can also side step to the left & forwards
Don’t back up constantly against a tall guy
Work on head movement and getting into range by slipping the jab and stepping forwards.
Feint and Change Rhythm
Use tiny shoulder and hip twitches to keep your opponent guessing.
Change up your speed
Do NOT Pause before throwing
Where ever you are, even slightly off balance learn to throw without a paused-set-up, or a pause and then throwing.
This is the same for wrestling, if you steady yourself, then shoot for a takedown, the opponent will see it coming a mile off.
Throw punches from unorthodox angles.
Do NOT Chase a counter-striker
See my second blog post – Tips for Boxing