I read an article in Golf magazine many years ago that suggested thinking of the round as three 6-hole rounds.
For the first six ho es, they suggested playing more cautiously, maximizing course strategy over shot making. For example, maybe take less than driver off a tee, aim away from trouble, aim for the center of the green or to the 'fat part' lf there are traps, figuring out where the best miss is on every shot, etc.
For the middle six, they say try to beat your 'front six' score by 2-3 shots. This might entail taking a few calculated risks, maybe using a 'red light, yellow light, green light' thought process on approach shots, etc.
For the 'back six' they suggest maximizing focus over each shot. Focus and energy flag on the last holes, so relax and distract yourself between shots, but then really get into a concentration zone over each shot on the last few holes.
I don't know whether this will help, but it is one of the few things i have ever remembered from reading advice and swing tips in a golf magazine.