Glazing is an important part of nearly all my paintings. The short definition is paint thinned with medium to create a transparent layer of color. I like to glaze things like creek beds, the layer of glaze creates a sense of a water surface where one can look down at the bottom of the creek to see rocks, sticks, etc, but still know they are looking down onto through water.
To begin acrylic glazing I mix about 20% fluid acrylic paint with about 80% glazing medium. (You can use heavy body acrylics but there is a risk of clumps not being mixed resulting in streaking when applied to the canvas). I mix these until the mixture appears the color of the paint. Being that the mixture is very fluid I use a palette with deep wells, so it does not spill everywhere. It is also important that glazing be down on a table rather than an easel for that same reason. In the instance shown I use three colors – This was a quick demo, but it was my intent that the different colors would show different levels of light refraction on the water surface. Color experimentation is very important when glazing – Some colors will have stronger degrees of opacity and even when thinned with 80% medium they might not give the transparent look I might be seeking.