Hey there!
There is no true guide on how to make TWC art. And honestly, your second post won't get you anywhere in asking for help; I will say it was slightly rude. However, I will guide you to the programs I use to make my art.
I use
Inkscape to get the base of most of my graphics. Then, I use
Paint.NET to make any minor cleanups. Then, I use
Adobe Photoshop CS4 to fine-tune the graphics, like make minor changes to the colors.
Sorry, but there are no "easy" steps to creating TWC art; it can take some advanced thought processes and some elbow grease. It can and will be hard work making TWC art, which is why we want to showcase it here. Other than what I've said, I can't help you.