Try to not do more than 25 minutes of cardio at a time if you are trying to lose weight. It puts your body into oxygen debt which can make your body convert everything it can into sugars because it thinks it needs to have that much more energy to survive. That is why you see people go for a very long time day after day on a treadmill, stairclimber and other cardio machines and never change or lose much weight.

Most people do too much to small muscle groups when working out. Biceps for instance are a relatively small muscle group. You only need to train them hard once a week 2 sets, 2 different exercises to see optimal growth. You can train them twice a week but you need to have 72 hours at least in between workouts to get optimal recovery and growth. Abs are another small muscle group. Large muscle groups need the same time off to recover but you can do more sets and more exercises for those groups like chest, back and legs.