Develop a good sprint workout. This will really benefit you. Lots of sprints. If you have access to a track anywhere near you, use it; if not, then use a field (road/blacktop being your last option, as it's the harshest of the three on your body). Sprints are great for targeting fast twitch muscle fibers, enhancing endurance, and improving cardiovascular health overall.
Shadowbox in between sets when you lift, and lift with an emphasis on grappling and cardio. In other words, think along the lines of moderate weight high reps doing deadlifts/clean and jerks, not heavy curls for the girls.
You can come up with tons of high intensity workouts that'll improve your cardio by stringing multiple exercises together. Like adding in sprawls between sets of pull-ups. Just remember the old saying to, "train smarter, not harder".
Also, sprints.
