I think the color scheme now is nice. If it needs to be cleaned up, you could refresh the current paint colors which would likely save you money (fewer coats). I might paint the chimney, since the brick above the roofline is different than below, which would unify it. For more curb appeal, I would trim the deciduous bushes so they look more orderly and don't interfere with the windows and shutters. Around the foundation, consider adding colorful glazed planters in a red that coordinates with your front door. It's an adorable house! Best of luck with the sale.