Fastpasses and the tiering system.
I know many people are not aware of the tiering sytem set in place by Disney until they try to pick rides. Then they get confused or angry. We do not want this.
Currently the only park without a tiering system is Magic Kingdom. Although, Animal Kingdom is tiering only in regards to the new Avatarland rides.
The tiering sytem allows you to choose 1 ride in tier 1 and 2 rides in tier 2 (if at Animal Kingdom, you can choose 3 rides NOT in Avatarland as well).
Also, you can not pick one ride more than once with your first 3 Fastpasses. You can hope to get that ride with your future (4th or higher Fastpass).
PLAN for this and use it to her plan your day in the parks. Mostly, ENJOY!!