One thing that was really helpful for my Eldest was going out on rides with other people. Proper Cyclists, instead of just his mum! Forum (across the road in t'other place) rides and so on. We also did a 50km audax which was a real challenge for him at the time. Unfortunately circumstances have prevented much cycling together for us in the last couple of years, although we're planning to put that right in the summer now that the younger Cub and I have our tandem. The big'un has absolutely zero interest in any kind of club or competitive stuff so that's a non starter for us but riding with the Audax nutters taught him a lot. He did BA 1 and 2 through school and mostly dismissed it as 'just stuff we already do' although he did pay a bit more attention to a different voice about some stuff.