To balance out your physique, you need to attack weak areas head on.
Here are 3 tips that would help:
1. Working the delayed muscle first at the beginning of the workout when you have the most energy and are most focused.
For example, once you get into the gym or start working out. You start working on that muscle.
If your weak muscles are legs, once you get into the gym. Start hitting legs before you do anything else.
2. Doing more sets
For example, instead of the normal 10 reps. Increase them to 15 reps or 20 reps.
3. Trying to increase the weight
For example, instead of doing 15 lbs do 25 lbs.