Get a good setup where you retract your shoulder blades and rest up on your traps.
The thing that has helped me the most is pressing more. I stopped doing tricep work and reps with dumbbells, and started going heavier on assistance pressing.
On DE day and ME day, my second exercise will be a heavy press for 3 sets of 3-5. The exercises I will use are bottoms up presses, 2 board, incline press, floor press. These are the lifts that help me the most with the bench.
This isn't revolutionary or anything, a lot of lifters do this, but with rack lockouts, 4 and 5 boards, etc...higher end stuff. Most people would be better to work on starting strength, though, I believe.