My advice, GO SLOW! Honestly, people are going to tell you get rid of those rules they are fear based. Well they are, but when you are starting out you are scared as hell! We got yelled at horribly, and abusively for 'rules' we set when we started out. It didn't matter what the circumstances, we were told that it was fear and not fair.
Going slow, really helped. The 'rules' went away because by the time they were an issue, we were comfortable. So I think that's what is most important. if it helps, don't think of them as rules. Think of them as, "I dont' know if I'm comfortable with XYZ yet." So you go slow. Just meet people, just do coffee, just talk on phones or internet until you find you are comfortable. When you are nervous, but not scared of X, then move onto X! Slowly but surely you'll find that the rules are gone.
Just understand, if you wait until you are completely comfortable, you won't be. Our rule of thumb has been when we are nervous, but not afraid. You don't get comfortable until after it's happened a few times and you realize it's not nearly as earth shattering as you thought!
Me: Late 30s pansexual poly.
DH: My husband of 19 yrs and father of 3 teen girls.
DC: LDR of +4 year