Does your copy make your reader uncomfortable?
SEO copywriting is not just stuffing keywords into copy. Doing this only makes it unreadable. It’s copywriting first and SEO second. You need to know the voice of the website you are optimizing. You also need to know how to be persuasive, a pseudo-psychologist understanding human nature. Never forget that your primary readers are humans, not search engines.
When inserting keywords, weave them into the copy with subtlety. They should never be an annoyance. The keywords should enhance the copy rather than distract. They add detail to inform the reader that the information is well thought out. You want to avoid stacking. Simply listing the keywords makes the copy completely uncomfortable on the eyes and gives your reader a headache.
The rules of general copywriting still apply. The humans that are reading your copy should enjoy doing so and have a right to do this without getting a kink in their neck from straining four inches away from their monitor to see if maybe they just aren’t reading it right. Never make your reader question their reading abilities when supplying sales copy or they’ll question whether they want to waste the time to be insulted while trying to figure out the riddle of what you’re offering.