Pizza is a bread dish. Most poor pizzas use too much sauce, too many toppings, and too much cheese until it's just a sloppy mess on a doughy disk and you can't appreciate the good bread.
Crust -- Must be thin and crispy. I despise thick chewy crusts and totally reject "cheese-filled", "stuffed" and other gimmick crusts.
Sauce -- Must be strongly flavored and brushed on thinly, not globbed on with a ladle like it was spaghetti sauce.
Cheese -- Must be a nice thin layer of cheese that can brown properly for a toasted cheese tastes.
Toppings -- Put all the topping in a single layer. It's all the pizza needs. Don't pile it high with toppings that just slide off the pizza onto your chin along with the extra cheese.
Cook it right -- Pizza should be properly browned. Toasted cheese, not melted cheese. The meats should be sizzling and browning, too. There are too many undercooked pizzas out there.
Everybody has their own idea about toppings, but I think a good three-to-five ingredient pizza is superior to a sweep-the-kitchen-mess. I change them a lot, but my current favorites are:
1. Italian sausage, black olive, & mushroom.
2. Ground meat, pepperoni, jalapeno, & onion.
3. Pepperoni, green olives & bell pepper.
4. Shrimp & mushroom.