On my computer I generated a splotch card and then painted each square with that color. Now I always have a reference when I'm trying to decide on which shade to use. It also keeps them tidy and in their own place, so it's almost instinctive where my brush goes when I need a color.
I spritz my jars with some water, then let it sit for a few minutes to soften the paint before putting my brush to it. It saves on wear and tear on the brush, rather than squiggle a wet brush into the dry paint, constantly rubbing the bristles. If I'm going to do some serious painting or calligraphy, then I'll drop some water into the jars with an eye dropper.
Most places you go on my website, be it ATC's or Hand Painted cards, journals made during workshops I've attended etc., will use Twinkles. I love them and their vibrancy and their little touch of Pizzazz.
Here are a few links showing what I've done with them, there are a ton more. ByHand/ThisThatMingle07/Chrysanthemum.html
6 Shakespeare quote
Kersal Card "Friend"
"Jokers & Jesters"