Don't listen to him ^ You'll want intense training in the summer, concentrating on Strength and Aerobics, and during the season you should have it on one tick below Very High.
Auto assign coaches works to a certain extent, but I've found that even after pressing Auto I can mess around with the coaches and make some stars go higher, without compromising the overall regime. So it doesn't optimise.
Make seperate training schedules concentrating on every section of your side - CB, FB, CDM, Box to box midfielder, CM playmaker, CAM, SM, Winger, Small quick striker, Target man.