Hey Molly - I know, me again - but I think the glow from the skull needs to be more 'ambient' as opposed to having one of your glowing objects inside it - what I mean is 'more 'pumpkin-like' - so that we we get a sense of the eyes, nose and mouth area glowing green - I don't think it's important that we see the light source itself - just the effect. The same might be applied to a small number of the skulls littering the floor - just for accent - but as you've established the logic of the green glow, you don't need to always connect it to a physical source - the audience will get it. In terms of rim light etc. I think you should investigate adding more to the cauldron, so that its top 'collar' punches out more and is more clearly defined - and I note you're using a white rim light - why not make the rim light that same greenish-glow - or use the pink light from the god ways as a way to accent objects further. At the moment, your rim lighting is a 'bright white' - but that colour isn't present anywhere else in your image?
Yeah, it's supposed to have a yellowish colouring to match the yellower god rays but I think the intensity is so high it's got rid of the colour completely. I'll go in and tweak it, along with adding the greenish glow to things, and see what comes out!