Gets its own page:
Confusing affect with effect. Do you immediately know the differences in what the following four sentences mean?
-- Her action affected the decision.
-- Her action effected the decision.
-- She told me she loved me without effect.
-- She told me she loved me without affect.
If the answer is no, you have some work to do. The rule of thumb is that for the great majority of times you want to use these words, effect is the noun and affect (to have an effect on) is the verb. Only rarely will you have occasion to use effect as a verb or affect as a noun, but you need to know the different meanings of effect and affect lest you blot your copybook.
Murray, Charles (2014-04-08). The Curmudgeon's Guide to Getting Ahead: Dos and Don'ts of Right Behavior, Tough Thinking, Clear Writing, and Living a Good Life (pp. 61-62). Crown Publishing Group. Kindle Edition.