I would say you need to improve your endurance first (unless you've already done lots of riding) and your high end stuff like Vo2Max and Threshold intervals second. But it's very general question. There are plenty of resources that will tell you how to do these things. I've just got back on myself and right now am focusing on incrementally spending more time on the bike, just riding and enjoying it. When my endurance comes up a bit more I'll start doing more interval work so I can keep up with attacks and improve my threshold for ITTs. Hope this helps.
I read a couple of months back in procycling (maybe feb or march) and i think they interviewed the fdj DS and he said something along the lines of 'train for half an hour longer than the distance of your race'. so
ie. 65km race = 65km + half hour extra once you get to 65.
I guess he is working on the theory that if you only train to the distance you need you will not be a fit as training past the amount you need to race.
I guess it was a bit vague but your question was also a bit vague