Seems to me that the colors are quite vivid (which some like, and some dont) and tend to clash a bit ...
I would have gone with about 3 times more dilution, to make the colors much less vivid and more ephemeral, with perhaps 1/3 the saturation, as well, to give some black background to contrast against. Lastly, I think I would not have mixed so many "hot" and "cold" colors together ... red-orange-yellow go nicely together, and green-blue-purple would also go nicely together.
Get some black construction paper and spray it with clear gloss and use that as a cheap palette to figure out what works best for you in terms of color scheme, saturation, and hue. (it's a lot cheaper than churning out a lot of bowls/plates that are unsatisfactory!)