Suggestion 1: Change your FOV frame to be a little tighter. Create a camera, then right click in the element tree, select add existing element, select the camera. Select it, you should have some lens options pop-up under procedural. Play with those a bit, to get a nice tight image without a lot of negative space. You may also have to play with moving the camera closer or further away to get it right.
 
Suggestion 2: in the newly instanced camera, select the tone map scale and move it either all the way to the left or just to where you can barely see your scene, right click your element tree and add in a few new lights(1 or 2 at first),Right click them, select disable shadows then goto their procedural tab and play with the FOV sliders, and set the brightness to where it bright enough to illuminate but not blot out the image. play with the coloring tabs(RGB) to make an acceptable atmosphere to start off with, add and edit lights accordingly(though remember only remove shadows from the lights that are for ambience, if it’s a direct character light leave the shadows on, also remember you can only have 8 shadowed lights, and about ~10 unshadowed depending on your PC’s processing power)
 
I have other things, but for now I’ll leave this.