My students all think my paintings start out sloppy. I'm trying to teach them the virtues of doing a loose under-painting and then gradually refining the color and the drawing. I like to get the initial drawing down pretty accurately. It's hard to make major fixes if the initial layout isn't generally accurate. I like to do the under-painting with a transparent wash. Sometimes I thin my paint with Liquin and sometimes I use turps. The Liquin seals the panel with a pretty tough film that doesn't lift when I paint on top of it and I generally like that. as you can see, my under-painting is pretty loose and essentially a value study.
If I want to keep working on the piece I will dry the under-painting with a blow dryer and then start blocking in the background and more color. While I do this I continue to refine the drawing.
Here's the finished product.