Here's what I do, which helps with both fiction and non-fiction:

Make simple declarative statements that tell the truth. Absolutely no ornament, just statements of fact, as best you understand them. You will find, in so doing, that most of the bullshit in your writing boils away. You'll also probably discover that you don't understand what you want to say nearly as well as you thought you did.

After you do this for a bit, you can start adding in the artfulness and phrasing. But the skeleton is declarative statements of fact.

It's interesting that this seems to deal with the "full of shit" problem and also the "boring" problem at the same time.