Every novelist approaches projects differently. My technique is usually to get what I call a semi-polished rough draft in place for one chapter before moving on to the next. In my case, that means that I’ve got most of the dialogue down as well as a goodly chunk of the action. Instead of polished description, I’ll usually have list of adjectives and nouns that I want to eventually work in. Some transitions will be weak; others will be non-existent.
I’ve found that a good way to remember where a character is emotionally is to return to the previous chapter to read and edit it. By the time I finish tinkering with phrasing and sharpening descriptions, I’m back in the world of my book.