Once you’ve settled on a world, gathered some food, and found a nice place to call home, it’s time to think about building. Housing is the logical first step. A decent house will provide safety from the mobs, a secure place to respawn upon death, and with a little bit of effort, something that looks great. On multiplayer servers, a well-designed home is a good way to leave a unique mark.
More often than not, your first home will be a hole in the side of a hill, a hole in the ground, or a structure that is a patchwork of whatever blocks you happen to have in your inventory (usually dirt or cobblestone). But if you put some time into it, you can turn that hasty survival shelter into a real architectural achievement.