Minecraft wiki entry for Shelters, associated text: Find a single large tree and use dirt (or another non-valuable resource) to pillar up to top and stay up there until day arrives. Jungle, tall spruce, and large oak trees are recommended. Mobs will not spot you if it is a large enough tree, and if they do, just take evasive action and move to the other side of the tree. Spiders could give you a problem, but hopefully, they won't see you. If the leaf canopy is big enough, you can actually dig up into the leaves, where monsters can't reach you. If all else fails, jump between treetops. When night's over, you can chop down the tree. Take care not to chop it down before you are done using it as a shelter, or the leaves may start to disappear, leaving you with nowhere to stand.