Does anyone else have trouble with these two words or is it just me? I can never remember how to use them correctly in a sentence. Remember? Perhaps I've never known how! Here's what www.dictionary.com has to say about them:
Affect1 and effect, each both noun and verb, share the sense of “influence,” and because of their similarity in pronunciation are sometimes confused in writing. As a verb affect1 means “to act on” or “to move” (His words affected the crowd so deeply that many wept); affect2 means “to pretend” or “to assume” (new students affecting a nonchalance they didn't feel). The verb effect means “to bring about, accomplish”: Her administration effected radical changes. The noun effect means “result, consequence”: the serious effects of the oil spill. The noun affect1 pronounced with the stress on the first syllable, is a technical term in psychology and psychiatry. Affect2 is not used as a noun.
Does that make it clear for you? It may have helped me for the moment, but I betcha when I have to write affect or effect again, I'll have to sit here and ponder whether or not I'm using it correctly!