1. affect / effect
These two words have specialized meanings in psychology, but in ordinary speech and writing, affect is most often used as a verb meaning “to act on or to cause a change” and effect as a noun meaning “a change that is the result of some action”:
How will the move to New Orleans affect the family? (verb)
What is the effect of this move on the children? (noun)
Note: Effect can also be used as a verb meaning “to cause” or “to bring about”:
The new mayor has effected positive change in the police department.
2. advice / advise
The error with this pair commonly results from mispronunciation and failure to distinguish between a noun and a verb. The c in advice is pronounced with the sound of /s/. The s in advise is pronounced with the sound of /z/.
Advice is a noun meaning “recommendation regarding a decision.” Advise is a verb meaning “to counsel”:
She always gives me good advice. (noun)
What do you advise me to do? (verb)
3. aisle / isle