Practice waiting. Wait in lines at the zoo, or the grocery store or anywhere. Give lots of encouragement (you are waiting so patiently, good job!).
Practice staying together. No running off, keep holding hands, etc. Malls are a good place to practice. If she gets lost, tell her to look for a mommy or grandma (or daddy/grandpa too, but usually women won't get that "creepy person" headache).
Practice her name, your names and your cell phone number. (Stuff she should be learning anyhow).
If your local zoo has characters, it would be a good idea to see how she deals with them. Mickey is adorable on tv, but in real life, that mouse is HUGE to a 4 year old!
Practice "dropping the wants". Kids tend to go a little nuts in the gift shops, with the "I wants". With our kids, we practiced at grocery stores and the mall. "I want this toy, I want that toy." "Yes, those are really cool toys, but today, we are just looking. Tomorrow, we will buy just one toy." (and follow through--tomorrow, buy just one toy) Lots of praise for not having a tantrum over not getting what they want today (you did a very good job not crying at the store, when I said we couldn't buy a toy today! Let's read an extra book tonight at bedtime!)
Oh, and work on her communication! If she can tell you "no, I'm tired and want to rest", it's easier to deal with than a 45 minute screaming fit. Listen to her needs and follow her lead. Lots of little meals throughout the day, lots of water and tons of bathroom breaks!
Give her some of her wants (sure, we'll ride Dumbo next--even if you are longing to do BMTRR, you suck it up), but make sure she knows that mom and dad get their choices too.
