Summarize the following:
Let's say you've done a fair amount of mining, but you'd like to make the process more efficient and profitable. At this point you should stock your inventory with plenty of basic equipment:  Food, iron pickaxe, shovel, & your best combat equipment Torches (several full stacks) Coal Crafting table and several chests Two buckets of water Ladders Bed (if you're in a multiplayer game that skips night) Place a crafting table, chest, and furnace on the surface, either at a cave entrance or anywhere you plan to mine. Stash your valuables (besides mining and combat equipment) in the chest, so you can retrieve them if you die. Each ore has a different distribution across the vertical layers of the world. Press F3 to view your coordinates and use the y-coordinate to guide you to the right area for the ore you seek (coordinates are given for PC edition):  Diamond: Only layer 15 and below Gold: Only layer 31 and below Lapis lazuli: Mostly between layers 11 and 17 Redstone: Only layer 15 and below Emerald: Only between layers 4 and 32 under Extreme Hills biomes Iron: Mostly between layers 2 and 58 No specific purpose: Focus on layers 10–15. There are three basic approaches to starting a mine:  A large natural cave gives you a headstart with exposed ore on the walls. Be prepared to fight plenty of mobs and take special care to mark the paths you take with torches or signposts. Dig your own vertical shaft to go straight to the best mining layers. Dig this in a 1 x 2 space so you never dig underneath your feet. When complete, build a way up with ladders, or pour water from the top to make a waterfall elevator that you can swim up and down. Dig an angled shaft at a 45º angle, clearing enough room above you to jump back up. Optionally, place stairs along the shaft for faster movement up and down. Once you're at the right layer, clear out an area three to five blocks tall, and extend it horizontally to search for ore. Since all ore besides emeralds come in groups of two or more, you do not have to reveal every single block to find the vast majority of them. Try digging tunnels one block wide, with three solid blocks between them. Remember, never dig straight up or straight down. Lava usually spawns below layer 30, but it can show up higher than that. Keep an eye out for embers, popping noises, and red ceiling drips that hint at nearby lava. If you do unleash a lava river, quickly emptying a bucket of water can cool it into cobblestone or obsidian. There's not much worse than mining diamond ore on the floor and watching it fall into lava. Dig around valuable ores first to check for this possibility. Even the most prepared miner can die in a freak accident. Place chests in well-lit, easy to find locations along your route back. Store your valuable ores in these chests to retrieve them on the way back, or to recover after you die.  If you have trouble keeping your sense of Minecraft direction, leave a trail of redstone dust to follow on your way back. When exploring a cave, consider lighting each chamber first, then mining on your way back. This reduces the chance of an accident destroying your loot. There are two structures that appear fairly often underground. Identify them by the change of scenery, and know what to expect:  If you see mossy stone, you're near a dungeon. These are small rooms with a monster spawner and zero to two chests of loot. You can destroy the spawner or leave it there as a way to gain XP. If you see wooden structures or rails, you've found an abandoned mineshaft. Look for chests inside of minecarts, and clip cobwebs with shears to get string. Be wary of spider spawners lurking beneath the webs. Minecraft cave systems can be quite expansive. If one branch ends in a dead end, especially one ending in dirt or gravel, there's often another cavern on the other side. Taking advantage of this sideways "drifting" can add major shortcuts to your mining.

Summary:
Stock your inventory. Set up base camp. Know where to find valuable ore. Get started. Spread out on the desired layers. Take precautions against lava. Leave a trail of torches and chests. Identify special feature. Look for nearby caves.