I train in Muay Thai so some of the 'tips' might not be too relevant but should carry across:
Footwork: The duel with footwork is trying to get the dominant position of your left foot (if youve a standard stance) outside of their right foot while also maintaining balance and agility. This will come over time but if you want to speed it up abit try light sparring but focusing on getting into better positions and not leaving yourself of balance by lunging or crossing feet. Keep on the balls of your feet and if you have distance to cover step jab DONT EVER lunge until your better or you'll get floored
Reflexes: Play squash seriously... Its a quick game and should help speed up your reactions or alternatively spar, focusing on quick punches rather than strong (that will come later with experience) or try Thai boxing, nothing quickens you up more than watching for punches, elbows, knees, and kicks
Strength: Lift weights and do plenty of plyometric exercises. Remember its isnt arm strength alone that makes a powerful punch it comes through the feet/legs then the hips turning over, the core turning, shoulders turning then the back/chest controlling the arm, and finally the arm extending. This technique will come easier as you get better. More fights are won with well placed punches than absolute wrecking balls, punches in bunches rather than one shot KO, this patience comes with experience.
So in short practice, practice, practice. This might not be what you want to hear but you cant be good without putting in the effort...
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