Minecraft wiki entry for Survival_in_an_infinite_desert, associated text: Instead of blocking the doorway with a door (you don't have any way to make those) or a sand pillar, block it with a cactus. Either a 2-high cactus, or a 1-high cactus on top of a sand block. This allows you to see out, and also damages any mob coming up to your door. Make sure you have at least a 3 x 3 clear floor area in the house so that you can stay out of the activation range of creepers (or at least, one creeper). Maybe on your first night just make a 1x1 hole in the roof (too small for spiders to come through) and no 'windows' so you don't have to worry about creepers or ranged attacks. There is the possibility that an enderman could fall through the 1x1 hole, but if one does, just don't look at it until it goes away.