Much of what I have put above is about the same rule: Avoid filler words and sentences. Most of us aren’t history majors; we don’t need to fit one page worth of information into seventy pages (and even historians try to avoid filler a little bit).
Look at what you write, look at it carefully. If there is a word that doesn’t need to be there, or a paragraph that tells your reader nothing, destroy it. Burn it with the flames of editing and never look back.
Don’t you dare waste my time with empty sentences, extra words, or pages where nothing happens. I promise you I will not force myself to read your vomit. I sincerely hope you’ll hold me to the same standard.