Sometimes I get so caught up in the act of painting, in the sheer joy of the process of manipulating the materials, that I don't see obvious compositional difficulties with my work. For that reason I like to place work out of my direct sight for a period of time, and then return to it with fresh eyes to see what needs to be tweaked.
I spent part of today self-critiquing the paintings nearing completion in my Reading a Garden series. I felt that several of them had a "weak" centre of interest (focal point, area of empahsis). That led me to search for a handoutt I had compiled several years ago when I taught a class on Creating Interesting Compositions. Reviewing it today helped me focus on what I could do to improve these paintings. If you have tricks up your sleeve that I haven't mentioned, please pass them on.
Defining the centre of interest
The centre of interest in a painting is not a single point or one person or object , rather it is a cluster of "objects" and can comprise up to 10 - 15 % of your painting. It is the area you want your viewer to be attracted to in your work, but you do not want it to be so strong that the eye stays there and doesn't follow a visual path through your work.
The best of everything
Your centre of interest requires the best of everything to make it stand out. Reserve strong value contrasts for this area. If you add a dark value directly behind or near a lighter centre of interest it will hold the eye. More detail, sharp/hard edges, strongest chroma, most texture, larger shapes, etc are all tricks for this area.
Bull's eye technique
Think about the centre of interest in your painting as a bull's eye. As you move out from the centre of interest, the areas should decrease in visual importance. That might mean including less contrast, smaller shapes, less detail etc. as you move out to the edges of your work.
Adding small touches of colour that are "outside" your colour scheme will draw the viewer's attention to the area.
Provide an area near/next to your centre of interest where the viewer can rest to allow "breathing space". This area could have less detail, subdued colour, large shape etc. This less interesting area will enhance the the energetic centre of interest.
If your centre of area is too large it will create visual overload, if it is too small it will be insignificant. Pay attention to the proportion of it in relation with the size of the canvas.
And... here's another way to look at it. Check out this great article by Dianne Mize on Empty Easel - 6 Ways to Create Emphasis in a Painting. Also see The Focal Point Debate by Dianne.
Her blog Compose is a valuable resource for anything having to do with composition.
How can this composition be improved?