During the dive, you and your buddy need to stay together so you can lend assistance to each other if necessary, not to mention because it's more fun. Ideally, stay within a couple of meters/a few feet of each other. Staying together is easier if you agree on who will lead, your relative positions, and the general course to follow until you both acknowledge a change. If separated, the general guideline is to search for each other for not more than one minute, then surface and get back together. In some instances it may be better to avoid surfacing to reunite. If this applies on a particular dive, it's important to agree on another course of action that reunites you within a few minutes.
The buddy system only works when divers stay together. Remember, it's your responsibility to stay with your buddy and follow the rules, guidelines and recommendations for each other's dive safety. No one can do if for you.
Plan your dive together and dive your plan together. Before each dive, run through each other's equipment using the predive safety check. Use the phrase Begin With Review And Friend to help you remember the checks:
BCD - Check adjustment, operation, low pressure inflator connection, and that tank is firm in the band. If appropriate for the entry technique, make sure it's partially inflated.
Weights - Check for proper weighting, and that the quick release system is clear for ditching. Weight belts should have a right hand release.
Releases - Make sure you're familiar with your buddy's releases and how they work. Check each other to make sure they're secure.
Air - Confirm that you both have ample air for the dive, that your valves are open, that regulators and alternate air sources work, and that you know where to find and how to use each other's alternate air sources.
Final okay - Give each other a final inspection looking for out of place equipment, dangling gauges, missing gear, etc.
Make a habit of performing this check - with experience, you'll do it quickly and almost intuitively. If it helps you remember, make up your own recall statement for BWRAF.
Now that you've read over the guidelines, test your knowledge with the Predive Safety Check Quiz.