Deciding what kind of mood or atmosphere you want to create in a book and sticking with it will pay off. Themes could include similes or metaphors drawing from words implying bleakness or emptiness, for example. A mood built and implied through descriptors, that compliment your narrative and plot is a good, but challenging, goal to have. So, how could you do this?
Listing any main theme/s. Including mood and atmosphere, specific emotions or characters traits crucial to the plot. This will be easier if you have even a rough plan of your story. For example, if a character is posh and rich, this will influence their speech, surroundings and atmosphere. Descriptions indicating space and money like 'vast marble flooring' and 'dazzling rings adorning her slim fingers'. Such descriptions accumulate throughout a chapter to create a semantic field (with is essentially means 'mood' build through consistently themed wording).
In terms of having a consistent voice, understanding your story theme/s will help. You might adapt your writing to suit a plot-line. Meaning writing consistently, without large breaks means your writing style will remain similar throughout. And any kind of 'voice' should be easier to maintain.