Find a block you like to do and then choose a background color such as: black, white, ivory, beige, brown, or navy depending on what will go with most of your scrap colors and then use different colors with your neutral to create a scrappy that is a little more controled. For instance: if you have a lot of blue choose a white for the background, if you have a lot of red use a navy or black as the background, if you have a lot of variety of colors an off white might work best.