New riders, when drinking from your water bottle, are required to spray a bit of water over their shoulder to cool the riders behind them. They are always grateful for the spritzing.
Yell out "hole" after passing it by veering wildly left or right...preferably left and right.
Perfect time to ask fellow riders to check your position on your bike, making sure you are correctly seated and fitted to your bike.
When it is your turn to take a pull make sure you take a long time at the front while gradually slowing the pace. Your fellow riders will thank you profusely for giving them a well deserved brake.
By following these and other "unwritten" rules of riding etiquette you will quickly become a cherished member of the group.