First things first. The pectorals, like most muscle groups only responds if you train them with intensity and allow them to fully recuperate. Basic pressing movements done for 4-10 reps are the ideal way to put on muscle. Anything less than 4 reps and you are basically training connective tissue and contractile power. So stay within the right range of reps and allow at least 4 days(I usually allow 6) between training sessions, while keeping your eye on nutrition.
Debunking the Flat Bench Press:
The popularity of the Flat Barbell Bench Press is crazy. Everybody uses it as an overall measure of strength and in 1000s of gyms across the globe guys in search of big pecs are flat benching there way into oblivion. The result is an unbalanced chest with shallow upper pecs. Whadaya do? I am not saying that you should eliminate flat presses... Also many people have potential for great development but they just press up as much as they can and never display 1 cut or striation at all. whadaya do? Big Joe's Chest Chiseler - That's what ya do! (ready to burst out your tank top).
-In my workout I start of with Incline Barbell Presses 3-5 sets of 4 to 10 reps cuz these enable me to use a heavy weight on a compound movement while allowing me to create more aesthetic development but hitting the upper pecs. I suggest that you vary the incline. Although I prefer the standard 45 degrees you can also take a flat bench and put it up and inch or two with a block and you get a nice low-incline movement which allows you to hit the pecs nicely. Since this is a power movement, pile on the weight for 3-5 pyramiding sets, aim for 8-10 reps on the earlier sets and go all the way up to a heavy-ass set of 4reps. Lately I have progressed to incline pressing just over my bodyweight. Keep your ass on the bench, chest high and keep your shoulders back and lats flared so that your pecs (rather than just delts and tris) do the work. As an alternate you can lower or raise the incline or perform it on a smith-machine...but barbells are better for me!
-Up next I suggest a movement that still allows you to move some weight but with more emphasis on isolated stress. Here I will do Dumbbell Bench Presses 2-3sets of 6-10 on a slightly-inclined bench. I find that this movement helps develop the mid-upper pec region nicely and hits the pec-delt tie-in areas. I hoist a pair of 75 or 80 pounders up and start repping away.
I like to conclude the last set of this exercise with a drop set.
After my hitting failure on my last set (usually 95 lb. dumbbells for 6 or 7 reps), I do a triple drop set: using a pair of 70s for 6, 60-65 for 6-7 and a pair of 50s to failure. I tell ya, your chest is gonna pump like crazy after these. It will be a blood flood in your pecs and you will be well on your way to that high shelved look that good upper pecs will give ya. So much that if Tyra banks was walking by she would take a second look (providing you are not posing your ass off-- you gotta look good but the honeys don't wanna see us showing off looking narcissistic!)
-To finish things off I have a couple of recipes. I like Flat Bench Dumbbell Flyes for 3 x 8-12. These give me a good stretch. Getting that stretch allows more neuromuscular pathways into those pecs, telling your brain--Hey, we got someone in the sternum department who wants more size! Stretching and contracting the pecs hard also brings out striations in your chest muscles. No matter how big you are, you will look good with striated pecs. Cable Crossovers and Cable flyes offer more pec contractions then regular flyes since they give you more resistance at the top of the movement-- I suggest you try 'em all to see which works best. Just don't go too heavy. The point of these types of motions is to etch detail and using too heavy a weight will force you to use the triceps too much. Sometimes I will also do a set of parallel bar dips to help hit the outer pecs too and might even superset them with flyes or crossovers. As ya can see I aim for eccletic approach-- using differing angles and what not to hit the pecs, but remember that nothing replaces the heavy basic exercises. No workout is gonna work for you unless you are eating right, making sure you got enough protein and all.
Also, I find that this workout allows for the most intensity. Keep in mind that some will recommend more sets or less. I suggest ya try my approach out for a few weeks and give other approaches a try for variety. Additionally, consult the insight of my collegues: Chris Meraz, AJ, Derek, Nathan, John Giljum, Anthony Church, Mahoney, Big Red, Jay Horowitz, Aaron Ciak, James Sadek, Bryan Kenny, Ben C., and Scott Duncan.