We have been opening family twice. Both times we got to the front gate (stayed on property) about 7:30 for an 8:05 PS at Crystal Palace on a day that wasn't Early Morning Entry. Just started talking to a CM that was at the front and they happened to be the ones that chose the family for that day. I'm not sure if they do the opening all over again at 9:00 for those that don't have PS or not. They gave my DD a certificate with her name on it that said Magic GateKeeper, some pixie dust to toss up, candy and oh yeah , we got to choose the magic word of the day. I chose Eeyore since she got everything else.. lol. Then they gave us a ride in one of the Main Street Vehicles down to Crystal Palace while everyone else had to walk.
So my advise is -
1) Get there as early as possible
2) Be friendly to everyone you see, because you never know who they are (even though you should be nice and friendly regardless

)
3) Don't ask to be the family. The CM's apparently don't like that much. We overheard other people just coming up and asking and were turned down.
P.S.
Sometimes it's just luck, so GOOD LUCK!