What runs me down is just how big a fictional world can become. I'm finding that writing a small travelogue for myself is really helping. Aside from being personally entertaining the act of writing about a character's interaction with a fictional environment comes with some pitfalls. Telling the tale of a world-wide epic requires some ingenuity when having the character(s) overcome the language barrier. Expecting the audience to believe everyone speaks the same language worked great in the original Star Trek, but is utterly useless when you don't have flashy lights and tight uniforms to distract the audience.
I have Numenarch trace a finger in the ground when he was communicating with the Spirits of Primordial Death. They spoke through their own echoes and impressions... impregnating the minds of those around them with their words. Numenarch utterly lacks those metaphysical contrivances at the time, so he resorts to a crude form of Pictionary to get the job done. I'd considered having him grow to be quite the artist as he traveled about speaking to different folks surviving in the darkened wastes of the Tenebrion, but it gets tiring figuring out something new and quirky for him to do in each of those instances.
I liked the idea of all the involved parties entering a trance whereby they could converse efficiently in their dreams. Describing the sensation involved was key-pressing stampede of my thoughts and ideas but in the end I felt like I would lose the reader utterly in something so heavy with nuance. It has to be something that feels natural to the reader, something that can be easily taken for granted later... keeping the story rolling hard across the page. The point is that the reader's own immediate surroundings end up destroyed by the words on the page.
Taking my time with the small stuff might be a short cut to avoiding big problems in the long run.
Working the echoes angle is old school. People are often led by impressions and in a world where your eyes are often deceived, such might be a more effective medium to paint a picture of one's self. Like if the whole world was nothing but smoke, you'd have to speak through it in a way that the pattern would be unique to you, the smog rolling with your words, the movements of your lips creating subtle details in the air. Working with the tenebrous environment itself as the medium might be the gimmick I've been looking for.
Think of all the neat 'up in smoke' puns I could throw around? Sold baby. Sold.