1. Only Official Rolls count, and Official Rolls are FINAL and cannot be rerolled.
2. Your roll is not Official unless the GM told you to roll it.
3. If you are taking an action, you must declare clearly and before rolling the die in order for it to be Official. If you roll without saying what you are doing, then you repeat what you did in the last round, even if it’s a bad idea.
4. A die must land on the table (or an object on the table) to be Official.
5. If it falls out of your hand and lands on the table — even accidentally — it is an Official Roll.
6. NO one else can roll for you unless the GM says so.
7. If something interfered with the die (someone’s hand, a book, etc.) — that doesn’t matter: it is an Official Roll.
8. If it is unclear what the die’s result is because it doesn’t land flat, then the GM declares the result or ask for a re-roll.
Also, a tip to GMs: Sometimes ask the whole table to make a roll (like Perception or Initiative). Then go around the table, in order. This makes it easier to get everyone’s roll, and it prevents cheating.