I'm 62 and the most important thing I've noticed is to rest a day after a hard ride. I've seen rapid improvement in stamina, strength (hill climbing) and speed by allowing adequate recovery time. I live in the Texas Hill Country and ride 4xs per week. 25-35 mi. on Tues, Thurs..... 40 to 50 mi. on Sat, Sun. But if I'm really tired, I take 2 days off. (Began riding earnestly after a long layoff in late July) I'm getting to the point where I don't even feel the need to take the extra time. I'd like to get to where I can do some randoneuring (sometime this fall).... When it's windy I like to get bent over in the drops. I didn't like that at first but now it's the easiest way for me to ride - and it really cuts out the wind.

(ps. Do hills to get strong quick .. but train, don't kill yourself with over effort.. They should push your limits buy not stress you to exhaustion. Recover then do more the next time)