Accent colors are usually compliments or near compliments to the colors in the painting overall. The accent is more intense and chromatic in its hue. There is no need to place the accent just at the center of interest. With the center of interest having the strongest impact, sprinkle the accent colors in other large areas of color to break them up. Just mixing swatches of color schemes in my sketchbook is a good exercise.
Color swatches using water soluble color pencils
'New Every Morning'
16" X 20"
'His compassions fail not, they are new every morning; great is Your faithfulness'