Warm-up thoroughly before you train to avoid injury and allow for maximum contractions while training. A cold or unprepared muscle will not contract to its full capability.
When you pick a weight for your first set of warm-ups, choose something that is embarrassingly light. Anything more will be too heavy. Trust me, if you do them the right way you will get more than enough stimulation.
DO NOT LIFT WEIGHTS, but rather you need to understand that you are supposed to stretch and contract the group of muscles you are training. Once you can stretch and contract your chest while keeping tension on it the whole time (never letting it go relaxed), you just add resistance to make the contractions harder. The amount of weight becomes unimportant, how hard you can contract your muscles is how you measure your progress, that along with the results you see in the mirror.
Don't overstretch your chest at the bottom of the movement. When you go down too far the tension comes off your chest and moves more to your front deltoids, which in turn will do most of the work when the contraction begins. You should feel more pressure on your pecs than your front delts and if you don't then you are going down too far. It's better to not go far enough than to go too far, so be conservative on the depth you use on all your chest exercises. The depth you use will change as you become warmer through the workout and as your flexibility increases, so as you become more flexible you can stretch further on each exercise. Remember, it's not a contest to see who can go deeper or be more flexible, it's a workout. So listen to your body and realize that you are different than the next guy. Be a leader, not a follower, and do what works for you. Let him try to do what you do and mess up his chest development rather than you trying to stretch as far as him and end up training your delts instead of your chest.
Keep tension on your chest muscles for the entire movement. Control the stretch the whole way down and control the contraction keeping the tension as high as possible right through to the end of the movement, only releasing enough tension for the weight to be slowly lowered again.
When you do any exercise, keep all your muscles tight. Hands grip the bar tight, forearms, upper arms, shoulders, chest, back. Keep your entire body tight so the supporting muscles give you a solid base and you can contract your chest much harder. Try a weight doing this, then go back and do it the old way and you will see how much lighter the weight feels and how many more reps you can get with it when your supporting muscles are all tight. Outside of the answer to the burning (or frying, perhaps) question of which superstar is really the psychopathic killer, Titus or Ryan, this is one of the best kept secrets in the sport of bodybuilding.
Keep control of the resistance through the entire movement, but pay really close attention to the start and end of the movement as these are the times when the tension on your chest can be diverted to other muscle groups due to a lack of concentration and those other muscle groups will end up bearing most of the resistance from that point forward, therefore getting most of the benefit, until you regain control of your chest muscles. If you have really well developed and strong front delts and/or triceps but a weak and underdeveloped chest then you are not a genetic freak, you have form and muscle control problems that are very easy to solve if you work at it and can keep your ego in check to train your chest.
As always, your muscles grow after you stimulate them and rest. Training more than once a week if you are training really hard is too much if you are a drug-free bodybuilder. It may even be too much if you are juiced to the nuts. You need time to recover and repair your body after you train. If you follow this program for your chest days and you are not making progress, you are either not eating enough of the right things, not doing the exercises the described way, or you are not spending enough time recovering.
If you grow a noticeably bigger chest after you follow this program the first time that means you trained your body rather than your ego, you rested and ate enough to grow, and you can now step to the front of the class because you have the discipline, work ethic, and brains to be a bodybuilder.