Eat before you are hungry. Drink before you are thirsty.
(Sorry, I couldn't resist!
)
Here are a couple of tips:
Find the good, steady riders and follow them.
Stay away from erratic riders.
On long rides stay away from the "red" zone early. You can always push it hard later in the ride if you still have some "gas".
There is more to cycling enjoyment than "dropping" people.
Don't go too extreme in getting the latest and greatest "racer" bike. They can be very harsh and cramped for a more "mature" rider. A bike that is 1% faster does you no good if you hate to ride it.