These two words, affect and effect, cause a great deal of consternation in English, no doubt because they sound similar and each can be either a noun or a verb. The quickest rule of thumb is that, in most cases, you affect something (verb) and cause an effect (noun).
Second side note: the less common meaning of the verb affect is to pretend or feign something (as in the example in the link where one can “affect a Southern accent”). I couldn’t fit that into the rhyme. 🙂
Finally, here’s your hopefully memorable quip:
From a cause, an effect, about that there’s no doubt;
And you’re effecting a change if you bring it about.
Affect as a noun is likely not what you meant,
So affect others’ grammar and send this to them.