I started a bit younger, in my early 40's, but I'll throw my two cents in given that you're only a couple of year ahead of me. The advice is based on the realization that we don't recover like 20 year olds, a year, a month, or a day off because of a training mistake costs us much more, and mistakes that lead to injuries or over training are also much more costly.

-Get a coach, one who works with guys our age. A good recommendation from a fellow age grouper cuts a lot of mustard. PM me if you need a couple. With the Net they don't have to be local BTW.

-Get a powermeter, and pick up a copy of Cycling Peaks software to use with it. You'll get epiphanies about your workouts you won't see otherwise, and you can replicate things when they've gone right.

-Get Friel's Cyclist Training Bible and read it cover to cover, at least twice. It'll help you understand training concepts.

-Listen to your body. If you're tired, rest. If you're sick, stay the heck off the bike till you're well.

-Eat healthy