Hi there, Jessica!
The Walt Disney World table-service restaurants are becoming increasingly popular, as more and Guests realize the quality of the food and the value of the service and experience. For that reason, Disney strongly encourages that a Guest makes advanced dining reservations (ADRs) for any restaurant s/he particularly wants to try or revisit. This will ensure that the Guest has a seat and can schedule time around that mealtime.
While walk-ups are certainly possible, there is no guarantee that you'll get the seating you want. If your goal is to maximize time at the Parks and go to table-service restaurants on an "in case" basis, then you'll be fine. Remember that all of the Parks offer many counter service options and food carts, none of which require reservations, and all of which serve great foods at reasonable prices.
If you do want to make your reservations, give a call to (407) WDW-DINE, or visit the
online reservations center.
Have a wonderful trip!
See you later, celebrator,
-Deborah B.