My hubby and I are still new to this, but as we live together we have some rules specific to that. We know where each other is and as a back up we have GPS apps on our cell phones( amazingly its paid off in non-poly ways, like when my car broke down). We are open about who we are with and there are check in times (ie im at the bar and will eoither be home by X time or will check in). Hubby and i dont share details of our intimate encounters, but do share that they have happened.
These are the specific ones that we feel are important, and allow the other to be in the loop.
As said previosly, rules are as diverse as the people involved. My advice would be to keep them around the most important items, where you are both comfortable. Communication is probably my most important rule of all, and my hubby does his best to keep me informed.
Hope that helps