Ahh yes the good old days, back when i had windows XP and a copy of MS paint to do my art, I wasnt that great back then, i never really considered shading and highlights or proportions or guidelines or different tools for that matter, back then i didnt even have a tablet, most of my art was done with a mouse and to my surprise it was pretty decent, not exactly the best but when your working on PS paint and using a mouse i guess its the best you can ask for.