Shoes first, and not the pretty pair. Walk in them on short days until the hot spots show up, because an extended hike will find every one. For the tent, pick something you can actually carry all day, not the roomier one that lives in the car. Water, a way to stay dry, a warm layer, food, and a way to know where you are cover most of a first overnight. The fancy extras can wait until you know what you hate hauling. How many days is this first one supposed to be, and are you staying on marked trails?