Maintaing proper form is a staple in my training regimen day in and day out, and so should it be for all of you. For one, if you allow your ego to take over your mind and start lifting extreme amounts of weight the only thing you will gain from that is an injury or a muscular mouth. You have nothing to prove to anyone but yourself. Leave your ego outside the gym. One of the biggest reasons why a lot of people train for years and never see any results is the fact that they use improper form all the time. Training with proper form decreases your chances of being injured tremendously and is the quickest way to muscle growth. So, remember to leave your ego outside and to always use an amount of weight that you can control. Its all about getting a great contraction on the muscle, not throwing weight around. If you take heed to this advice you will notice an increase in muscle mass and be on your way to reaching the goals you've been trying to attain for so long.