Thank you so much for thisTutorial , the instructions are so clear and concise as to what to do,
I have been a heavy GIMP user for years since that was the standard tool when I did web production and graphic design. GIMP is very powerful and does a ton of other stuff in addition to drawing (photo editing, basic animation, etc) .
A good drawing tablet is almost a necessity. I use a XP-Pen Deco 03 Graphic Tablet with GIMP , It's a great tablet. For slider adjustments, spot, brush edits it's pretty good.