|Greetings from the Critique Club!
COMPOSITION... I think the idea behind the shot was interesting, but its execution has left a photo that doesn't have uniqueness to it - has a snapshot quality to it. The crop cuts off a corner of the yellow swatch and the rest seems oddly placed. It is hard to photograph paint samples in an interesting way... you're right - perhaps more would have given the shot something more... More swatches mean the possibility of more of a "fan" effect, and you could have arrange the swatches so the colors follow in a continuous tone. The shape of the fan of color samples could have sweeped across the frame...
Just before clicking always make a final check to ensure all your important elements are within the frame.
TECHNIQUE... I would angle the shot so its directly overhead - I think that approach works best here. At the angle chosen, the light is being reflected back at the bottom of the swatches, which has resulted in an uneven light across the samples.. Other than that, its a clear, clean image.
OVERALL.. A lot more samples could have helped.. Still life shots have the benefit of allowing you all the time in the world to shoot, so try different angles, view points, setups, lighting scenarios. With lots of shooting under your belt you'll soon realize what works and what doesn't, not to mention you'll hone your eyes to pick out interesting compositions with your subject matter. Good luck in future challenges!