I liked this blog by Jeff Haden entitled: 40 Incorrectly Used Words That Can Make You Look Dumb. You can read the full article at:
A few examples are:
Adverse and averse
Adverse means harmful or unfavorable: “Adverse market conditions caused the IPO to be poorly subscribed.” Averse refers to feelings of dislike or opposition: “I was averse to paying $18 a share for a company that generates no revenue.”
Affect and effect
Verbs first. Affect means to influence: “Impatient investors affected our roll-out date.” Effect means to accomplish something: “The board effected a sweeping policy change.”
How you use effect or affect can be tricky. For example, a board can affect changes by influencing them and can effect changes by directly implementing them. Bottom line, use effect if you’re making it happen, and affect if you’re having an impact on something that someone else is trying to make happen.
Compliment and complement
Compliment means to say something nice. Complement means to add to, enhance, improve, complete, or bring close to perfection.
I can compliment your staff and their service, but if you have no current openings you have a full complement of staff. Or your new app may complement your website.
Discreet and discrete
Discreet means careful, cautious, showing good judgment: “We made discreet inquiries to determine whether the founder was interested in selling her company.”
Discrete means individual, separate, or distinct: “We analyzed data from a number of discrete market segments to determine overall pricing levels.” And if you get confused, remember you don’t use “discretion” to work through sensitive issues; you exercise discretion.