Acrylic is a difficult medium to work with, but you have a good grasp of how the colors work together I'd say what would help the most is to take time to practice contrast and how it influences the shapes of a piece. Your aim was to avoid using outlines, I assume, and this is mildly difficult to accomplish without soft and hard edges to make up for the lack thereof. Contrast goes hand in hand with lighting, though, and both are a very effective way to paint, either with mood or without. Explore modes of contrast and your art improvement should skyrocket!