Shadon,

Also forgot to mention the art of maximising your time. As KSH and Pedal Wench have said, you really need to amp up the power to really maximise your training. I try and do this at least once a week - but obviously it depends on your schedule and fitting in time to mix up your training.
Even if this only consisted of half an hour a week of full-on riding, outside your comfort zone (but obviously within safe and healthy limits), with you really pushing and pumping up the speed, it would help.
Obviously you also need to mix this with a longer, more consistent paced ride too.

Like Pedal Wench said - entering for an event is excellent motivation to get out there, put the miles in and really give it your all in training!
You need to concentrate on all the important factors: distance, speed, cadence, stamina, strength, rest, fuel and FUN!!