I don't know your personality type...like things simple and just go do it, or like to obsess and study, or whatever.
But, I have really enjoyed a book called The Ultimate Ride by Chris Carmichael. Mostly it is still far beyond me, but even now I have been able to use some principles that have really helped.
This year I plan to train more seriously through the winter, and I expect to use more of the principles.
There is all kinds of info in there on a huge variety of ways to improve...all the different ways to pedal, spin, use cadence, HR, periodization, etc.
I enjoyed it. I also liked the sports psychology part...the goal setting portions, etc.
Glad you're loving your bike!
"The best rides are the ones where you bite off much more than you can chew, and live through it." ~ Doug Bradbury