I don't like the word rules...rules were meant to be broken...I think far and few between are the couples who have never broken there own rules sometime. It may have not been deliberate or meant to happen it just does.
Think more of it as guidlines.....know each others limits of what you are both comfortable with, keep it simple and basic. Talk over on what works for both of you and agree on that ahead of time.Trying to read each others minds is hard and unfair especially if you read it wrong.
Don't be afraid to talk to each other openly but respectfully even after an encounter has started, making sure if you question something, a simple are you ok is all it takes and make adjustments in the middle if necessary. If one person in the group is not happy about something everyone can feel the anxiety.
If you know what types of people interest's you and your partnerr or what you may be looking for or to try, it can rule out a lot who don't fit the plan right from the get go. Don't be afraid to excuse yourselves and go off privately and talk, chances are the others may need that too.
Also be ready and open to change, and adjust those guidlines as you grow into the lifestyle and become more open to new ideas and situations. It is all about changing and growing together, having fun together at your own pace.