KSH- Here's my two cents worth:

1)- When you are riding are you hyrdating and eating? If no, drink, eat. Must do. NO alternatives on that one!

2)- Do you have time to work out at the gym- i.e. weights, etc. I am currently putting together a routine set up for me that is designed to increase endurance- basically upper and lower body strength building (let me know if you want my program on private mess and I'll send it)

3)- Do you have hills where you live??? Hills are good for training those legs!
I do hills on all of my rides- spinning up hills works the best.

4)- Interval training- to get up consistent speed I recommend this type of workout- you can do it on flats as well as hills. Basically what you do is ride like a madwoman for a few minutes and then back off- rest- do it again. I will do this kind of training when I am working on speed over time. Its an old trick from running.

5)- Are you eating before you ride? Also important. I always have something even if it is 5:00AM ride time. I drink a mixture of juice and water in those early AM rides just to get quick energy.

Hope this helps. I'm sure the rest of the crew here will add some more tips!