Edit ruthlessly for clarity and concision.
Try to generate transparent, effortless prose — effortless for your reader, that is. (It is never effortless for you.) Each word needs to justify its existence. Sentences, paragraphs, chapters, characters, subplots, arguments… all need to justify their existence. Are they really needed? Will removing them compromise the piece, or purify and sharpen its impact?
Question every punctuation mark that you use — other than a period. Add more periods constantly! Break long sentences into smaller ones. Use smaller paragraphs, smaller sections, and smaller chapters.
Don’t use a big word when a small one will do. (That sentence originally had much bigger words in it).
Be definite and decisive; avoid qualifiers like mostly, probably, and sort of. Avoid unnecessary intensifiers like very, really, and incredibly. Scorn assertions that something is certainly, undoubtedly, or clearly true; you are overcompensating and implying the opposite. Spurn exclamation marks — a sentence will speak for itself if it is dramatic, startling, or witty. Deploy crutch words like actually, obviously, honestly, basically, and literally with great caution. Never use the word ‘literally’ in a metaphoric way.
Prefer active and positive phrasing. “It was determined by the committee that this action was probably the most inexpensive” is wretched, pallid prose. “The committee determined this action was economical” is better.
Simplify, simplify, simplify. Good editing is almost always a matter of simplification.
Remember, you’re not simplifying your ideas. You’re simplifying the means by which you communicate your ideas — so they will reach more people more effectively. It’s a matter of filtration, distillation, purification.
Use minimum means for maximum effect (and not affect).