Like FoeRender, I'm working on upping my skills, specifically I'm looking to do multi-layer blends, I have all the mediums, thinners, etc. generally needed, but the one thing I really have trouble with is getting the consistency of the blend right, I know "skim milk" is the target, but how do you know when you get there? usually it gets so thin, that it looks like i'm just wetting my brush instead of actually getting paint on it.