I think it came out darling! Sign painting is hard and like RD5 said, it's difficult because of the space limitations.
When I teach modern calligraphy, I always emphasize "consistently inconsistent." So while the bounce may look like it's random, it is usually following a pattern of some sort. This evolves naturally over time but in the beginning, it may be helpful to use guidelines as Jean suggested. But I like to do an upper guide and then a lower one so I know where to "upper bounce" and "lower bounce." If the bounce is too big, it becomes awkward.
Also, you want to try to avoid a large "wave" in the pattern - so a string of letters going up and then down (like up a small hill). You want to alternate the up and down so you can't actually see the pattern (hope that makes sense). Otherwise, it is like when I write on a chalkboard without guidelines, it all goes uphill or down!
Hope that helps. I really do like your sign!