Here's an exercise that involves making shapes and rearranging them.
The first part is to generate the shapes.
1) Paint a sheet of cheap paper all over middle value grey.
2) Paint another sheet all over black.
3) When the papers are dry, tear them into interesting shapes. Keep the sizes varied.
The second part is to arrange the shapes on a sheet of white paper
1( Move your shapes around until you feel them click into place.
2) Glue the shapes to the white paper, or take a photo of the arrangement.
The Third part is to let the arrangement inspire a painting. You can use the shape collage as a value guide, or not. These can be any size you want. The palette for your paintings can be as limited or as expanded as you please