Tutorials/Wool farming

Mechanics
You can get wool by shearing sheep, killing sheep, or crafting it out of string. Shearing sheep is often advantageous as it means that they can regrow their wool by eating grass. They will eat grass as soon as it grows, meaning observers can be used to detect this and activate dispensers, which can shear sheep if their hitbox is in the block in front of the dispenser.

The wool will fall off and will usually go into a hopper for collection.

Automatic sheep shearing design
There are many designs that can be stacked to make large wool farms. The sheep can also be dyed to produce different wool colors.

How to build an automatic wool farm

 * 1) Place down a dispenser facing horizontally.
 * 2) Lay down grass blocks 1 block lower and one block in front of the dispenser.
 * 3) Build a pen out of glass (preferably the color of the sheep).
 * 4) Lure a sheep inside.
 * 5) Put an observer underneath the dispenser facing at the grass block to power the dispenser.
 * 6) Put a shear into the dispenser.
 * 7) Place minecarts with hoppers underneath the grass to collect the items.
 * 8) Make a room full of chests that the minecarts bring the wool into.