Well, here we go again. I make heaps of mistakes with grammar. What about you? Here are some classics, courtesy of Jon Gingerich. I hope they help some of you.
Since and Because
“Since” refers to time. “Because” refers to causation. e.g., Since I quit drinking I’ve married and had two children. e.g., Because I quit drinking I no longer wake up in my own vomit.
Disinterested and Uninterested
Contrary to popular usage, these words aren’t synonymous. A “disinterested” person is someone who’s impartial. For example, a hedge fund manager might take interest in a headline regarding the performance of a popular stock, even if he's never invested in it. He’s “disinterested,” i.e., he doesn’t seek to gain financially from the transaction he’s witnessed. Judges and referees are supposed to be "disinterested." If the sentence you’re using implies someone who couldn't care less, chances are you’ll want to use “uninterested.”
Unless you’re frightened of them, you shouldn’t say you’re “anxious to see your friends.” You’re actually “eager,” or "excited." To be “anxious” implies a looming fear, dread or anxiety. It doesn’t mean you’re looking forward to something.
Different Than and Different From
This is a tough one. Words like “rather” and “faster” are comparative adjectives, and are used to show comparison with the preposition “than,” (e.g., greater than, less than, faster than, rather than). The adjective “different” is used to draw distinction. So, when “different” is followed by a preposition, it should be “from,” similar to “separate from,” “distinct from,” or “away from.” e.g., My living situation in New York was different from home. There are rare cases where “different than” is appropriate, if “than” operates as a conjunction. e.g., Development is different in New York than in Los Angeles. When in doubt, use “different from.”
Bring and Take
In order to employ proper usage of “bring” or “take,” the writer must know whether the object is being moved toward or away from the subject. If it is toward, use “bring.” If it is away, use “take.” Your spouse may tell you to “take your clothes to the cleaners.” The owner of the dry cleaners would say “bring your clothes to the cleaners.”
It isn't a word. "Impact" can be used as a noun (e.g., The impact of the crash was severe) or a transitive verb (e.g., The crash impacted my ability to walk or hold a job). "Impactful" is a made-up buzzword, colligated by the modern marketing industry in their endless attempts to decode the innumerable nuances of human behavior into a string of mindless metrics. Seriously, stop saying this.
Affect and Effect
Here’s a trick to help you remember: “Affect” is almost always a verb (e.g., Facebook affects people’s attention spans), and “effect” is almost always a noun (e.g., Facebook's effects can also be positive). “Affect” means to influence or produce an impression — to cause hence, an effect. “Effect” is the thing produced by the affecting agent; it describes the result or outcome. There are some exceptions. “Effect” may be used as a transitive verb, which means to bring about or make happen. e.g., My new computer effected a much-needed transition from magazines to Web porn. There are similarly rare examples where “affect” can be a noun. e.g., His lack of affect made him seem like a shallow person.
Irony and Coincidence
Too many people claim something is the former when they actually mean the latter. For example, it’s not “ironic” that “Barbara moved from California to New York, where she ended up meeting and falling in love with a fellow Californian.” The fact that they’re both from California is a "coincidence." "Irony" is the incongruity in a series of events between the expected results and the actual results. "Coincidence" is a series of events that appear planned when they’re actually accidental. So, it would be "ironic" if “Barbara moved from California to New York to escape California men, but the first man she ended up meeting and falling in love with was a fellow Californian.”
Undoubtedly the most common mistake I encounter. Contrary to almost ubiquitous misuse, to be “nauseous” doesn’t mean you’ve been sickened: it actually means you possess the ability to produce nausea in others. e.g., That week-old hot dog is nauseous. When you find yourself disgusted or made ill by a nauseating agent, you are actually “nauseated.” e.g., I was nauseated after falling into that dumpster behind the Planned Parenthood. Stop embarrassing yourself.
Clancy's comment: Mm ... When I first learnt the Thai language, several words kept popping up that caused me grief. It's a tonal language so you have to do your best to get it right. One such word was khao, which can have up to nine different meanings from glass and rice; even mountain. However, over time I quickly learnt to restructure what I was about to say very quickly to avoid any embarrassment on my part, or confusion on the part of my listener. Hence, when I'm writing, if I come across some confusing grammars such as above, I quickly learn an easier way to say it. Makes for a better book, and your reader unknowingly appreciates it. I hope!