Well if you mean training, then what i suggest is some cardio, maybe running or skipping. Sit-ups, push ups just the usual. Once you begin training however you will get a better idea of what you need to develop. Fitness will come naturally during training, and during you should push yourself, so when you spar you are the fitter and smarter man in the ring. Also youre trainer generally knows best so listhen to him, just remember that the first 2 weeks are always the hardest, once you get through those you set. Sweat more bleed less...