Hi Chris
I think it looks really nice though there are three elements that are about the same size and all are craving for attention making the eyes jump all over the place and not knowing where to focus on.
I'm guessing the blue mushroom on the front is your focal point so the character next to it could be a bit smaller (since it's about the same size) and/or less bright so it doesn't compete with the mushroom's light (something like the smaller blue character on the far right would work better on him). Or you could make the yellow character be the main focus so removing some of the brightness on the blue mushroom would make him stand out much more.
I would also try making the mushroom house much smaller so it looks farther away and also making it less bright as well, also could be positioned a bit more to the right so it kind of balances the scene a bit more.
The water looks really nice but I would also add some darker shading the farther it is from the main mushroom.
One trick you can use is to add a new layer in multiply mode on top and paint with a 15% dark blue on most parts as to add some ambience and reducing the lighting on most of the objects (minus the main focus one).
Hope something of this is helpfull to you 
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