fmscout.com seems to have some helpful tips for FM11 and other versions. (I haven't spent much time there, but I should. My skills need training.) One page deals with training, and talks a bit about what goes into training and what you can do to improve it.
Here are some things that affect player development:
Naturally better facilities mean better training and faster development. Facilities also determine what options a player has for individual training focus, higher quality facilities will allow you to individually train more attributes such as positioning and off the ball.
This is a long-term strategy, rather than a short-term one, because you won't be able to upgrade those facilities overnight (or at all, in some cases). If you have basic facilities and can't upgrade them, then some players may not improve much and you can't do a lot about it.
A coaches [sic] training ability in a specific training category is shown by a star rating, this rating is affected by coaching attributes, determination, discipline and motivating and also by the number of schedules that the coach is assigned to.
More of a middle-term strategy. It's better not to sack coaches midseason for cost reasons (honestly, I don't know if you can even do it; I haven't tried), but if it's possible, it would be a way to upgrade your training, assuming that there's an available coach who'll sign with you.
Professionalism is a hidden personality attribute that determines how high a workload a player will be happy with on a training schedule, the higher the workload the harder a players trains and better improves. A player with professionalism of 10 or higher will be happy with a very heavy schedule (one click from heavy to very heavy only), players with a lower professionalism will be unhappy with an intense schedule and be less effective and prone to injury, keep them on a medium intensity training schedule.
This isn't something you can change, but presumably something you can determine. If you increase a player's training load and he responds poorly, you've probably hit his professionalism limit.
You might also consider changing the player's workload distribution: you can't change the percentage that goes into anything other than match preparation, and of course decreasing match prep time will limit the amount of time your team spends on that, but maybe it's worthwhile if your team is playing well together but just isn't doing that much.
This is all secondhand knowledge, and I apologize for that. I'm sure it would be better if I could actually show you a training plan that worked for me, but I have to admit I haven't tried any of these tips either. I just haven't poked around at training much, other than to do different plans for different positions and to train players in new positions.