In this case, “Friends” stands for analogous colors: side by side on a color wheel. "Lovers" are complementary colors: directly opposite each other on the wheel.
Sample colors directly from your photo to make a quick, easy and effective palette. Try Photocopa: upload your image, explore the different hues that make it up, and build a stunning color palette.
Keep your graphics looking clean, and not too overwhelming. If you think there’s just something that isn’t working, ask yourself if you can cut down the number of colors in your palette -- ideally to just three.