A turbo trainer is an excellent tool to really improve your cycling. This is down to a variety of reasons, one of which is the "clinical" and "unpolluted" training environment you can create... No traffic lights, roundabout, cars etc.. to break your rhythm. You can also keep very close tabs on power/effort output and train in a very controlled power range for any given period of time.
As with any training, it comes down to "what are you trying to improve". The training on a turbo for a 10 mile TT would be different to that if you are focusing on road races for example (although both would share similar workouts).
If you let me know what you would like to improve upon, I would be more than happy to suggest a few workouts. Its amazing how some structure on the turbo will make time fly! Learn to love thy turbo, and you WILL get faster.