My chest is far from huge, but I thought I'd mention what is starting to work for me since my chest lags
If your chest lags pre-exhaust it, Ive been doing this for abit now and I can see it is starting to work for me
All bar work just used to give my delts a workout, now I do incline flyes followed by incline DB's, the key is to not rest very long between the flyes and incline db press, do 1min or 1.25 absolute max, you see your chest recuperates 75% of its strength after 1 minute or so, so KEEP IT LOW and intense, as you are trying to pre-exhaust it!!
The most important factor though, is to feel the muscle working, if you dont; it wont get trained, simple. Put all your concentration into squeezing the hell out of your chest, also tense it during your rest period, dont give it any chance to relax. Tense it every opportunity you get, you dont have to make it obvious.
Sometimes I will do drop sets on the dumbells and forced on the flat bar (following incline db's).
My chest is really pumped after this. The most important factor is keep your rest periods down and form has to be 100%.
Focus on your chest, not on the pain.
This is what is starting to work for me.
Good luck dude
Oh I forgot to say, you'll know the next day if youve hit your chest, I used to get really sore delts and a little soreness in my chest - no good, but I have worked hard on eliminating this and now my delts barely get sore at all whereas my chest feels like it has been worked hard. Its all about form and concentration.