delericho
Legend
Atavar said:So, what advice would you offer me that can help make this a good experience for everyone in my group and help me to avoid common mistakes that others in my situation have made?
Treat her the same as everyone else. Be very strict with yourself over this - no 'hints', no side-quests, no additional magic items, no NPCs tailored to work with that PC, and so on and so forth. I recommend also considering making all rolls out in the open henceforth, to demonstrate your impartiality.
I recommend explaining to your girlfriend that this is the way it's got to be - if you aren't impartial then the game will likely implode, so she has to understand that while you're at the table she's a player, just the same as Bob over there.
Truth be told, though, the major danger with the GF-as-PC thing is where it all goes wrong. If the other players object, or you find your enforced impartiality is taking a toll on your relationship, the only real thing you will be able to do to recover the situation is to step aside as DM - removing the GF from the group isn't going to be an option (unless it's her idea).