I wandered too far to go look for sheep and now I'm on a completely different island. How do I find my way back to my house?
If you have the correct supplies you could craft a compass. A compass will always point to your original spawn. To craft a compass you will need to arrange 4 iron ingots and 1 redstone, like so:
If you lack these supplies and want an alternative to using mod's you could press F3 and this will display the debug screen. On this screen should be 3 coordinates (X, Y, Z). If your house is near your spawn (the place where you first appeared within that level), then you could just walk back to (X:0, Z:0). Generally you'll spawn within about a 100 blocks of (X:0, Z:0).
If you're fine with doing so, you could open up your world in one of the programs listed in the Programs and Editors page of the Minecraft Wiki, to view your map and attempt to figure out where your home is in relation to where you currently are. Eihort looks like a great tool (and is compatible with Windows, Mac OS X, and Linux), because it shows the coordinates of where you are currently hovering (so when you find your house, you can easily locate it in-game via F3). If you don't need something quite that powerful, mcmap and Tectonicus are also good.
In the place that you are lost, copy the coordinates down on paper. Then make a chest and put all the good things that you have in that chest, and after that kill yourself/ allow yourself to be killed. Then you should spawn at home. At your house copy down those coordinates, then go to the first set of coordinates you copied and all your stuff will be in the chest, then you can use your home coordinates to get home again.
If you don't want to use any external tools then you could build a tower where you are and climb to the top. Then turn the render distance to maximum so you can see as far as possible.
This may enable you to spot some features you recognise and will also give you a reference point in case you get lost in the future.
I'd recommend Zan's Minimap, which is a clientside mod that gives you a great, customizable map. Of particular use to you is the feature that allows you to set waypoints on your map, so you will never lose a certain place again.
Just be aware that the 'Threading' option will corrupt your world in a solo game if turned on (so leave it off).
And, if your bed is far both from x0 and z0, you can try seedscope.net and use it to teleport back to the last bed you used, but without losing your stuff.
My favorite technique, however, is to make a new home where you are. Start over, and eventually you'll find your own place and can link the two.
I found out ways to find your way back to your house.
Make sure when you're traveling, you bring a map, otherwise you won't find the way back. The map doesn't show all the places in your world since you haven't explored it yet, but it's the best way to find your way home. Normally when you spawn in a world, you get a map in your inventory so you don't have to craft one.
Compasses are another useful tool since it points to your spawn point. The crafting recipe is below.
Don't worry if you lack these materials, there's more!
In case you get lost, always mark your home using beacons. Make sure they are taller than trees and your house. You can make a big tower of dirt blocks with torches, or out of glowstone [the best]. If you haven't marked a beacon, yo won't be able to find a way back.
Build a New Home
If you're still lost, it's best your make another shelter before nighttime. Build your house using wood or build it within mountains.
Make sure you use some of the wool you collected from sheep and wood blocks to craft a bed. Coal or charcoal, and sticks, which are made of 2 wood blocks; used to make torches. 4 wood blocks are for crafting table. 8 cobblestone blocks are for the furnace. 8 wood blocks make a chest. make sure you brought food too incase you starve. if it's night, then you have to wait till morning. Don't craft a bed, this will change your spawn point! Make sure you bring you mark beacon incase you still can't find a home, and bring a map too!
Those are my ways of finding your way back home. if those don't work, then you're doomed!
/gamerule keepInventory true so you keep your inventory. Then just drown yourself or jump of a mountain but DO NOT do this if you have not slept in a bed back at your house or set your spawn point there.
If you don't want to do that then type this in your text bar:
/gamemode 1. This should change you to creative mode so you can look for it by flying.
If you have cheats on this world, I would recommend going into Creative mode (/gamemode c) and finding the house from there. If your house is near your spawn, and you are completely and utterly lost, then you could also create a Creative mode copy of your world using the "recreate" button on the Singleplayer menu. Write down the coordinates using either F3 or Fn-F3 to bring up them up and then go back to the other world and find your way!
Try remembering the biome your house was on. After this, press the F3 key, showing your coordinates (along with other info). Search your house around the world origin (0 X, 0 Z coordinates). Of course, you are hardly ever spawned EXACTLY at the world origin, but you will still be spawned close to it. Unless you built your house far, far away from the origin, this method is valid. So make sure the coordinates are closing to the origin, as you move. Search your house well, even if it means a long journey. To prevent this from happening again, just make a screenshot (with the coordinates on the screen) using F2 with you in or near the house. You can find the screenshots in the Screenshots subfolder from the .minecraft folder, found in Users/your username/AppData/Roaming (This path is valid on windows 7). (I used this method quite a lot, ranging from finding villagers, to Nether Fortresses and End Strongholds).