Minecraft wiki entry for Tips_and_tricks, associated text: Find a cave, and explore a branch of the cave, placing torches to light it as you go. If the cave branches off while exploring the current branch, go down one of the paths at random, pick one to explore. If the branches seem to go deep, you can craft fences or walls to block off all but one of the paths, so that monsters won't come out of that area to surprise you from behind. When you come back, you can just pick up your fences to use them somewhere else (or replace one with a fence gate, for more controlled access). If you have jack-o-lanterns, you can use them to point the way back to the exit, or make other markers. (See the Navigation tutorial.) Note ores as you pass, but don't start mining until you've made the area safe, by lighting it up and blocking off unexplored areas. Remember the pickaxe tiers -- if you only have a stone pickaxe, don't try to mine gold or better until you've made an iron pickaxe.