To create a perfectly symmetrical body you must routinely take a body inventory. The first time I heard of the concept was while reading Arnold's "Education of a Bodybuilder". The approach is two fold.
First, you want to asses the damage. Where are you the sorest and where have your joints been taking a beating. The second assessment is on weak points. Take pictures and look to see where you need EXTRA work. Weak point training does not mean ignoring everything else. Be smart and think like a sculptor
In July when we decided on the 12/3 contest we took pictures and had a complete inventory. I looked for weak points and one was tricep development. While I never stopped working biceps, I added extra reps, sets, or posing holds for triceps. After 6 weeks the proof was trully evident and now relaxed, my triceps stand out.
If you take a good assessment you will find that your energies will be shifted properly and you will avoid plateauing.
Train hard
-Alex