I am pretty new to this kind of stylized renderings and I am always looking for things I can do better.
I like it! But – I suggest that you avoid making the watermelon-seeds actually be “3D,” and here’s why. In the pizza-slice on the left, the highlights above the “smile” draw simple-but-effective attention to it. Whereas, on the watermelon-slice (that’s in the same frame at the same time), they steal attention away. If a pepperoni-slice can be two-dimensional, so can a watermelon seed.
Otherwise – the stylization looks perfect to me. I noticed, and I like, how you treated the edges.