Each painting's process varies but here is how many of them begin!
I start by mixing different proportions of gloss medium and pigment in cups. Then I often prime the canvas with water and one color. I drip the colors on top of the wet paint one at a time, I give each color enough time to move around the canvas and start to settle before adding more. Then I move the canvas and the paint to get the desired effect. I let the painting dry for a day, then cover the layer with a clear gloss medium and let it dry for another day or two. Once that layer is dry I do the same process as many times as it takes to get the look I want then I go in with a small fine brush to add in details and fix anything I don't want in the painting.