Devote a day a week to training your “weak parts.”
It’s easy to devote time to training your strengths. If you have powerful legs you’ll probably find yourself devoting time to them before another bodypart. Likewise, if you are in particularly good shape from a cardiovascular standpoint you may spend a half hour on the stationary bicycle before dragging yourself over to the weights.
Now, I think having a favorite workout is terrific because that may be the thing that gets you into the gym in the first place. But be sure not to neglect your least favorite one, because that may be the one you need most. Take one day a week and focus on your less favored exercises or bodyparts. If you hate training your calves and abs, set aside a day in which you train them exclusively. If you find yourself shunning cardio work, go for 45 minutes on the treadmill on an “off” day.
By prioritizing our weak points we have the ability to make them strong.