pound the crap out of your chest, whatever exercises you feel really hit the chest. some people may feel it more with dips, some wide grip bench, some dumbbells etc...
whatever you do, POUND it until it is dead, so you can barely bench the bar for 10 reps. you must take each set to absolute failure and do a few forced. the aim is to cause microtrauma to the muscle tissue - then your body's adaptive response is to grow back a little stronger than before.
then rest as long as is needed. be it 3 days if you are 20 and superman or a week if you are an older fellow. you must let it recover completely then pound it all over again.
for example if you scratch your skin, there would be some dead skin cells under your nails if you looked under a microscope. no real damage to your skin has occurred so there is no adaptive response. this is akin to all the morons at the gym going through the motions without any strain - it doesnt cause the muscles damage so there is no adaptation - no growth. now imagine your girlfriend catches you cheating and tries to dig your eyes out. she draws blood all over your skin, she rips it open. this is damage and your body will respond by growing back the tissue a little stronger than before - called a scar. the secret is giving the skin time to heal completely, only at that point is the new skin (scar) stronger than before. of course the muscles dont take as long to heal but giving them enough time is essential