I'm starting to see some real improvements in my riding. Today I did 25 miles at 18 mph overall, no drafting. Half of that was intervals, 20-22 mph for 3 minutes and then 15-17 for 3 minutes, 5 times. The other half was a steady tempo cruise at 18.5 mph for 10 miles. And I'm still alive!
I'm realizing that a lot of this is mental. Looking back when I was averaging 14-15 mph and being stuck at that level for a year, I realized that I wasn't really pushing myself hard enough. Riding more, and riding with faster riders helps, it shows what I can possibly do (even if I'm drafting), and then when I pull by myself, I push harder because I know I can do it.