It's best to do this in creative mode, if your gonna do it legitly though, you need lots of food, diamond armor + diamond sword & a bow with about 200 arrows



1. Find a stronghold

Locate it using alot of ender eyes, you can get ender eyes from killing endermen.



2. Go to the end

Activate the portal by putting the ender eyes in the empty slots on the sandy looking block.



3. Destroy all the healers

This way the Enderdragon can no longer heal when it gets hit, the healers are on top of the obsidian towers

You need to do this or else it will just keep on healing and you won't be able to kill it.



4. Attack!

The Enderdragon can no longer heal from the healers and is more vulnerable.

This will take quite some time.



5. Kill it

After attacking the dragon for a long time, it will finally die.

It will start dissolving and disappear in a purple explosion.

After killing it, you get tons of XP and a pool/portal that leads you back to the real world.

But first you have to go through this long speech of 2 people talking.. xD

Finally, you will respawn at your spawn point with about 100 levels gained.

Then you do it all again! :D



Video tutorial (not by me)