Some artists like to approach a painting one section a time, only moving onto another part of the painting when this is totally finished. Some gradually work from one corner outwards, finalizing a certain percentage or area of the canvas at a time. Others paint individual elements in the painting, for example each item in a still life, one at a time. If you're using acrylics and want to blend colors, it's worth trying.
This is an approach I use very rarely, but find useful when I know that I want to let part of the foreground in a painting intrude into the background, such as waves dashing up a sea cliff. When I don't want to have to try to fit the background in around the foreground right at the end.
