Get a punching bag!! If your comps are 2 minute rounds, set a timer and work on effective strikes, no fancy stuff, just hard and fast techniques, for that amount of time.
You need to spar as much as possible and as many different opponents as possible, and spar hard, condition your mind and body to deal with punishment.
If there's no-one to spar with then shadow sparring can be an effective substitute, again set a timer and work on effective techniques and good footwork. Use visualisation to create an opponent and concentrate your strikes to specific targets.
Good luck and keep punching mate!