Your pecs do two things, push forward and bring your arms across your body. Keeping this in mind, when training chest I have two main movements I perform:
a pressing movement
a flye movement
Position the Bench
The angle of the bench when performing any chest movement will determine where on the chest you hit, from top to bottom.
On an incline, you will workout your upper chest. With a flat bench, you put the emphasis on the mid pec. Working out on a decline hits lower pec.
incline/flat/decline barbell press
incline/flat/decline smith press
incline/flat hammer (you can also adjust the incline from slight all the way up to 45 degrees)
incline/flat/decline dumbbell press
flat cable machine
I feel upper chest usually needs more work to balance out the chest, as compared to decline bench positions.
Cable Crossovers: You can do this with a bench or standing. The crossover angle at which you pull can be changed to hit lower, mid or upper pecs.
Pec deck: The seat on a pec deck can be moved slightly up or down to change where you hit the muscle.
As with most body parts, I would switch the order with each workout and change bench angles or just workout tempo to hit the muscle a little differently each time to ensure complete development.
Generally speaking, I will hit each exercise for 3 hard working sets after an initial warmup of 2-3 sets of the first exercise I decided on that day.
Any questions? Just leave a comment below.