That's great advice regarding the scapula Haz and I would also like to add.
CLARKY
Don't have the incline to high and also change the angle every workout until you feel the right angel which suits you bests.
I prefer db's doing incline and once you get the bells above your head bring your shoulder joints kinda back into the bench and into your scapula, so in other words try and lock your shoulder IN instead of having them out so try and make yourself more narrow by pulling your shoulder in and back, hope that makes sense. Its very important.
Keep both feet flat on the floor but just a slight few inches back from your knee, now pinch your shoulders together so you squeeze them into the bench and scapula and push down and forward with your feet, you your trying to push yourself slightly up the bench but you cant because your shoulders are locked into it but the pressure from the tensed thighs and feet placing is producing a hard solid core and very ridged.
Brace lowering your diaphragm, breath through your belly and push your oblique's out and start pressing. Were you start with the bells either above your head, chin, nipples is up to you how your body feel, but you will get the groove right once you do is correctly. The best correct way for performance would be to have all the power and weight under your body, so in other words, bells above directly below inline with your elbows and shoulders so when your press and unlock the lower is straight through and that will result in more power which will end up with more tissue stimulated.
Press down while your doing all the above and on the way up slightly bring the bells inwards so it puts more tension on the upper chest and away from the triceps, I see loads just pressing straight you but their chests are sh1t, bring them slight in and don't lock your elbows, just keep a nice slow pace thinking about how you got your body in position and keeping in this ridged state.
I know it may be a few things to think about before actually doing the movement but honestly it takes me less than 1-2 seconds to set up and I go all out and I can see my chest red full of blood all over the top of my chest.
Not sure if I explaianed that right but any areas I didn't let me know and I will go over it again, again that's just my view but you watch the pro's do it
