The following is Sotonia CC's 'guide to club runs' but I'd think you could apply most of it to any other club.
Everyone is welcome to join the Sunday club runs. These are essentially social rides rather than training runs. Just turn up at the meeting point at the allotted time. There are a few simple points that can help make sure that you can enjoy your time on the bike: There are many experienced riders in the Club who are more than willing to offer advice, so please don't hesitate to ask. They can also advise you on the best set-up for your bike.
Equipment
Your bike needs to be serviceable - It should go without saying that if you are riding on a public highway your bike needs to be in good working order and comply with the Highway Code, but it does not need to be the latest and greatest featherweight machine. So long as it is mechanically sound, it fits you and the tyres are in good condition and fully inflated, then you should be able to enjoy your cycling. Bring a couple of spare inner-tubes (to fit your bike!), tyre levers and a pump so that you can quickly sort out a puncture and continue riding with minimal delay. Mending a puncture at the side of the road is no fun and takes a lot longer than just swapping an inner-tube. Save the glue and patches for when you get home.
Sensible clothing
It has to be said that cycling-specific gear can make a huge difference to comfort and can reduce fatigue, but for the short easy rides it is not essential. Dress in suitable sports gear according to the weather conditions and remember that the wind chill factor on a bike is considerably greater than if you are running, so it is particularly important to think about this in the colder months. It is also advisable to carry a lightweight rain jacket which can double up as an extra layer in cold conditions. A cycle helmet is advised but not compulsory.
Drink
Maintaining the body's hydration is vitally important in any endurance sport and it is essential that you carry appropriate amounts of fluids. Even a small deficiency in hydration can cause a significant drop in performance and will speed up fatigue. Allow around 750-1000ml of a water-based drink for every 2 hours of riding, more on hot days or if you are riding very hard. Specialist sports drinks are good but not essential.
Food
It is always a good idea to bring a bite to eat, even on short rides. Hunger or a drop in blood sugar levels soon accelerates the feelings of fatigue. Bring a couple of energy bars, cereal bars or bananas for a 2hr ride and more for longer rides. Better to have too much and take it home that not have enough.
Club riding etiquette
Cyclists generally ride in groups for social reasons, training benefits and race strategy. Regardless of the kind of group you ride with, some universal etiquette applies. Knowing and applying a few simple rules can help you be an effective, considerate and safer group rider. This applies equally to novice and experienced riders.
You must remain constantly aware of those around you and remember that your movements in a group affect everyone. For example, if you get out of the saddle on a climb, be conscious that your back wheel is likely to drop back six inches or more unless you control your bike correctly. Pedal continuously at a cadence and speed that is consistent with the riders in front of you. If the pace slows ahead of you, try to soak up the distance between you and the rider in front by pedalling softer rather than braking hard.
Keep you eyes on the road ahead rather than the riders themselves, and try to anticipate any changes in the riding pattern. Be alert, but stay relaxed. Point out and call if you see, pot holes, traffic, parked cars, horses and anything else that you would want to know about. Also warn others before turning left or right. Riders towards the rear of the group should also be attentive to approaching traffic from behind making others in the group aware when appropriate. The usual call is "car up" if a vehicle is coming from behind and "car down" when from in front.
SOTONIA offer a number of rides, differing in both distance and speed (see the SOTONIA web-site at
www.sotonia.co.uk for further details). Most are social rides and no one, especially junior or female riders should be dropped from the group or left unaccounted for. However, if you chose to ride with the fast group and the pace is too fast for you, then do not always expect the group to wait. If in doubt ask them before you set off. Keep the group leader informed - If you decide to leave a group and ride on your own, inform the leader of your intentions or, at the very least, inform one of the other group riders. It is leader's responsibility to ensure that everyone in the group is accounted for at regular intervals throughout the ride. This is made far easier if it is known who has left the group.
Show consideration to other road users - We share the roads and should always be courteous. In order to allow vehicles to pass, the group should ride as a single unit with riders keeping to no more than two abreast. It is a requirement of the Highway Code that riders should form single file on narrow or busy roads or when negotiating a bend. If it becomes necessary to ride in single file, gaps should be left to allow vehicles to overtake more easily. When singling from 2 abreast, the rider on the inside should move to the front and the outside rider should ease off to fall in behind. The group should slow down and announce their presence when passing horses and their riders and should not make any noise or sudden movements that would be likely to unsettle the animal. Equal care should be taken when passing wild animals such as ponies, sheep and cows.
Maintain an even pace - If you are riding next to someone, be aware of your relationship to his or her front wheel. Constantly upping the pace when the rider draws level with you (half-wheeling) is rude and disruptive. The groups should always reform if they split, for example on hills or at road junctions. Climbing hills is often best achieved by individuals choosing their own pace, when this occurs the group will reform at the top. If it becomes necessary for the group to stop, a safe place should be sought to avoid inconvenience to others. In winter and wet conditions mudguards should be fitted as a courtesy to other riders, even bikes which are not designed for mudguards can be fitted with "race blades".