The two key ride-day points have been mentioned... Stopping and hooking up with a good group. Personally, I prefer traveling light and comfortable with brief stops, typically for fluids, both in and out . Hooking up with the right group takes some good self-knowledge. What feels like a good, invigorating pace early on may leave you toasted at mile 75. If you begin to suspect it's too fast for you, it is. Let 'em go and hook up with a slower group. That beats the 25 mile death march to the finish after you're toasted been dropped. Also, you want a group with the same mindset (willing to stop, etc.).

The other piece is preparation, which includes training and pre-ride tapering, rest and nutrition.

I think there's been some good discussion in the past... you might do a search in Training and Nutrition and Road Cycling.