If you're having trouble establishing a mind-muscle connection with your triceps then begin the workout with something that puts the muscle into a shortened position, and work isometrics (holding the contraction) to help with that. Try a pushdown variation. My favorite for this is the reverse-grip pushdown.
Make a concerted effort to roll your knuckles back towards your body and hold that for a 2-3 count for 3-4 sets.
"Every day, I hear someone say, 'I'm too fat. I need to lose 25 pounds, but I can't. I never seem to improve.' I'd hate myself if I had that kind of attitude, if I were that weak. I can lose 10-40 pounds rapidly, easily, painlessly, by simply setting my mind to it. By observing the principles of strict discipline that bodybuilding taught me, I can prepare myself for anything."