When I am making Mixed Media artwork I like to keep a pre-cut Mat "window" nearby to help me isolate parts of my work in progress that may actually be more exciting than if I kept the "whole" piece intact. I have been criticized for giving up too soon on "resolving" a whole piece and I understand that comment. I even at times feel a little guilty for reaching for my mat window, but I also appreciate that I respect my visual eye and if cropping is what is called for....that is what my artistic intuition tells me. Some guidelines that I use when I am making this decision to crop or cut up a piece of work is does the section I have highlighted show more composition integrity and or excitement than the piece as a whole? Sometimes eliminating "noise" or complexity is helpful. Are the color relationships keener in the smaller section chosen? Do I get more drama, serenity, mystery, movement etc. in the portion of the artwork that I have chosen to feature. These are some ways to think about should you crop or not.
A great way to learn about cool design when making abstract art is to take a look at Jazz album covers from the 1950s for examples of hip style, design, color and composition. Many people get STUCK in making the same shapes and sometimes even make the same size shapes over and over. That is not art, it is wallpaper. And I should know, because I have been a member of that club for years. So I began going online and looking at lots and lots of album covers form the 1940s-1950s. This album cover shown, was designed by Burt Goldblatt for American jazz tenor saxophonist Don Byas. In particular I am interested in Goldblatt's use of the very large pink/white boomerang shape (a very common 1950s) element and it's relationship to the green background. Take a good look at this album and notice how line, shape, color, value relate to each other. You can indeed learn so much by exploring old jazz albums for inspiration for your own artwork.