I tend to paint very thin layers, and get my depth of color by going over and over with almost a dry brush, creeping up on the values and colors that I want. Some people prefer work more wet into wet to get more of a brushwork feel with acrylics, so I’ll give you some suggestions for making the acrylics move around the canvas more easily.
In wet on wet work, colors blend together and are affected by the colors adjacent and underneath. Each brush mark is softened by the wet color painted in, edges are softened and colors are mixed. Since acrylics dry quickly, the paint itself must be altered to allow the slower drying and ease of blending
It’s important to keep high humidity for wet into wet in acrylics, so begin by using a spray bottle of water on the canvas to keep it wet. Spray frequently, but remember to use some acrylic medium now and then, to retain proper adhesion.
A few drops of Flow-Aid in the water will keep the acrylics open a bit longer allowing them to spread more easily. I use about 6-10 drops to a pint, especially when outside in the wind. It’s the one additive that doesn’t seem to otherwise change the properties of the paint except for the longer openness.
If this isn’t enough, matte or gloss medium will keep the paint open longer and make it easier to spread. This won’t change the viscosity of the paint, but as you add more the colors will become more and more translucent. Careful choice of colors can add a nice depth to the color without actually glazing. Slow-Dri blending medium will do the same thing and keep the paint open even longer.
If you want more brushstroke to show on the surface of the canvas, start by using a very heavy body paint. Heavy gel medium will also increase the viscosity of the paint, reduce drying, and add to open time.