Ok, first of all, this has the feeling of an outdoor scene with the current lighting, which generally means shadows should remain quite sharp. However, you could try to incorporate a little bit of an outdoor feeling by adjusting the lighting.
If you can, create a sort of AO-like render. Grey everything out, no specularity, no ambience, just plain grey or white diffusion. Then light with a light-dome and render it out. Try and get the render's light as soft as possible.
If you want to go try something really hot, attempt to adjust your lights in your lightdome do cast light in the colors of the point they represent in the sky. White/yellow towards the horizon, babyblue going upwards, darker blue going to the top. Maybe adjust brightness to match up with the sun position. Kinda like simulating some HDRI. It can add just that extra bit realism, or maybe that little extra special touch.
The resulting AO-like render can be merged with your main render in photoshop, using either multiply or overlay mode, or whatever fits your wishes. Also dont be afraid to fiddle a little with the levels of this AO layer when compositing, it's a powerfull tool to adjust the look you're after. The general idea of this layer is to make the endresult look more tactile and lifelike.

If you want to make glows, draw them in photoshop. Use screen or dodge layer(s) with blurred versions of your renders. If you're looking to add specular glows to specific objects with specific materials you can render dedicated passes in bryce too. (full black material except for the specular channel).

I know all this sounds like horror to the purist brycers, but I'm a great fan of using post effects to improve an image's overall appeal.

(_/)
(='.'=)
(")(")This is Bunny. Copy and paste bunny into your signature to help him gain world domination.