If you want to put in the extra effort, it could be a good idea to distribute some reeds along the shore. But mostly I meant the fact that the tiles you used for the water are pretty visible as such. I suggest to either make them larger and intersect more, so that the seam vanishes, or use a different water from a mod such as this one:
https://psteamcommunity.yuanyoumao.com/sharedfiles/filedetails/?id=2488192521

@Baryonix what would you change or add water-wise? A shoreline?

Not bad! The water area could be improved, but overall a good map. The colors you chose fit together well.