Years back these rules used to be part of every seminar I did. While I would like to take credit for these I have read them several times over my education but they really came together for me when Tundor Bompa wrote about them. These rules applies to all strength training from beginner to advanced. Not keeping these in check can also lead to injury for the advanced.
Law #1 - Before developing muscle strength develop joint flexibility.
This is pretty simple when you think about it. Think about a simple barbell squat. How good would the technique be if the hip or ankle flexibility was off?
Another way to look at this and the one I see most often is when advanced bodybuilders want to move into Powerlifting. The size of their muscles have inhibited their joint flexibility and a certain degree of this flexibility needs to be restored to be able to squat, bench and deadlift without getting injured. I am not saying they need to drop muscle but they do need to get back their joint flexibility. There are many ways to do this but the best is following the rest of these rules and adding in light loaded stretching and iso holds.
Law # 2 - Before developing muscle strength develop the tendons (what attaches the muscles to the bone)
This is accomplished through more GPP training with loads under 50% of maximal.
Law #3 - Before developing the limbs develop the core.
The core is the muscle of the back - spinal column, entire abdominals region. This has been beat to death so there is no need to go over the importance here but it should be noted when strength begins to feel "good" these are the movements that always seem to get dropped first.
Law #4 - Before developing prime movers develop the stabilizers.
This falls back to the body must learn to stabilize force first, absorb force second and finally produce force.
This is all pretty basic stuff but important to note just how important this all is to not only physical development but injury prevention as you progress.