I have found that doing isolation movements first gives me a better pump and that I am working the muscle better. By starting with the big compound movements first I found that I had to do a few sets before really feeling anything.
Therefore my Chest workout goes something like this.
Warm up: 2 x 15 reps of Cable Crossovers or Pec Deck
Flat Bench Dumbell Flyes 4 x 15, 12, 10 and 8 reps as the weight increases.
Incline Barbell press/Machine Press 2 x 10 to 12 reps. Third set is with heaviest weight possible for about 8 reps then drop weight and go to failure which is anything from 10 to 20.
Flat Dumbell press 3 x 8 to 10 reps.
This is my chest workout. I rotate this every 6 weeks i.e. the first 6 weeks start with compound movements,
then 6 weeks start with isolation movements. This I keep up throughout the year including pre contest
All the best - Pat "Bully" Warner