A little late to the discussion, but i try to think of:
A as in Affect; A as in Action:
Affect is a verb (something affects something else)
Therefor, Effect is actually a noun; it comes attached to an article (the effect, an effect)
I remember this from my science fair days in 6th grade:
"The Effect of Blank on Blank"
and in the actual report:
"...how blank affected blank."
Exceptions:
Of course there are exceptions, just to confuse you.
Affect can be a noun when you are talking about someone's speech pattern, i.e. their peculiar affect
Effect can be a type of verb when you are talking about whether one can effect change.
So you can effect change effectively by being careful about how your use of effect and affect affects others, making sure your positive effect is not lost on your audience due to your peculiar affect.
Yikes.
Their/There
I always remember that there is location because you can either be here or there.
Then I remember that their implies ownership, because it has the word "heir" inside it, and heirs own possessions passed to them. dorky i know, but it's so habitual i can't stop it now.
Two commonly misspelled words that i just memorize:
Desperate
Separate
Sound the same, spelled differently.