In between exercises I try to do a tabata style workout. I will do high intensity Cardio from 2-4 minute then hit up my next exercise.

Between sets I like to get another body part in like calves, abs, shoulders etc. I like to keep my HR up, intensity and focus high and efficiency crisp. I like the gym and all, but I want to be in and out. Plus breaking up my cardio keeps me good about doing it.