A couple of days before you plan to open have a big party and invite all your friends and family. Have them come all at once and let them order off the menu. Call it a dress rehearsal, and treat them like customers. You will be surprised at the small things you have forgotten. For my second store I forgot to get dough cutters. Imagine my surprise when we went to get that first pot of dough out. As far as ordering, get more than you need. Actually, get more than you THINK you need. The dress rehearsal will help because you will see what you actually use, like how that big tub of “whatever” only lasted 10 pizzas, etc. The suggestions of the soft opening were spot on.
Just to help out with some numbers, for an expected $1000 day I prep or make sure I have: 125 lbs dough, roughly 30 quarts sauce, about 75 pounds cheese, 40 lbs sausage, box of pepperoni, 4 #10 cans mushrooms, 2 #10 cans peppers, about 10 onions, about 5 pounds bacon, about 6 quarts each of broccoli and clams, about 5 sliced tomatoes. Most of my other toppings are quick to prep, like sliced cherry peppers or sliced olives.
Keep careful track of how much of everything you prep and how much you use. Keep notes on what you tend to run out of and when. Good luck to you.