In this tutorial, I will be using a program called 'Alchemy'.
Alchemy is a free drawing program. The only bad thing about Alchemy is that you cannot erase or undo. Since we will be working in black and white, we can just change the color to white and use THAT as an eraser.

You can download Alchemy here.

First, open Alchemy. Your Screen should look like this (To find that bar, move mouse up!):



Your going to want to turn on your 'Mirror' Effect (Unless you don't like to mirror):



Draw out your sketch:



When done, export your image:



Select your export name and destination. Make sure its a .jpg or .png. Use the drop-down box, just adding .jpg/.png WON'T WORK:



Keep the settings that pop up. You want width to be 1024, and if you change height, the width size changes.



Open it up in your selected image editor thing. I use gimp, for example. When you put it in, change size from 1024x708 to 1024x512(After you Color/Shade, You resize it to 512x512 at the end):



Trace it, fill it, shade it, etc. After you're done, flatten it and size it to 512x512. Then you get your product. Mine happens to be:



I didn't go into detail with the actual texture making, this is just about making sketches.

I do not own GIMP, I do not own Alchemy. I made this tutorial myself. Please don't steal it. If people ask, link them here, or tell them about Alchemy.

Thanks.
~Tubba