A good starting point to improve speed is 3 × 3 minute rounds of
relaxed shadow boxing, 3 × 3 minute rounds of punching a floor to ceiling ball or you can try a paper target hanging head height from the ceiling (The idea is not to hit the paper but simply make it move with the air generated by fast punches), 3 fast one hundred metre sprints.
The best single way to improve your UFC fighting speed is to practise as much
shadow boxing as you can concentrating on
relaxing your muscles as you fire out quick combinations.