Aerobic and Strength work are important in pre-season to get your players physically fit. You can't do too much of this when the season is underway as players will be getting tired enough from playing matches.
I have the overall workrate at intensive so that I can have them working hard on Strength and Aerobic as well as doing bits of everything else. Ease up by the final week of pre-season so players can get their conditions up for the first game of the season.
Training during the season
Set up schedules, don't just go with General and GK. I have separate groups for Defenders, Midfielders, Forwards, and Set Piece Takers.
Coaches
You definitely need to get some new coaches. I've not sacked any yet but Parkin doesn't appear to be much use. A fitness coach is imperative to bring in at the start of the game given the fitness work you'll be giving the players in training.
For further discussion on this topic and to share your tips, please click here for the 'Training' thread in the Message Board's Games Room.