I'll chime in too.
My training hasn't changed much. Things have gotten more intense. For example, where I once did one-minute, 200 watt intervals, I now do one-minute, 500 watt intervals. And I have put a lot more emphasis on base training. Last fall/winter, I slowly built up to 20 hours of base riding by December/January. I had planned to do that again this year, but a knee injury hampered my training.
The other thing the OP needs to consider is his age and base level of fitness. When I started riding, I was 27 and had absolutely zero experience doing any sort of endurance sports. While I played lots of team sports when I was young, by the time I was in high school, I had narrowed my time to playing golf. And once I was in college, I spent most of my time drinking (I went for the freshman 40). I started playing ice hockey in college and continued that afterward, but beer-league hockey is not a great way to stay in shape. So for me, when I started riding and racing, I was in such horrible shape, it took a long time, about five years really, to become competitive.