creating/dowload:

first you need to do is go to this site:
www.minershoes.com

on this site you can create your own skin.
when you're done, press Download and save it somewhere you can find it back.

installation:

now go to:
www.minecraft.net and press the button Profile
scroll down and press the button Choose File, sellect your skin and press the button Upload
open your minecraft and enjoy your new skin!

please, comment and give diamond