One pair of misused words that I find really annoying is your/you’re. It isn’t hard to learn one is possessive and one is an abbreviation  (for you are), but so many people use the incorrect word which shows a lack of knowledge and attention to detail that does not represent them , their content or their business well.

Your: refers to something you own
Is that your bike?

You’re: an abbreviation of ‘you are’.
You’re going to work tomorrow.

Yore: referring to the past, although it isn’t often used now
In days of yore, a Lady’s ankle was never seen.

Although these three words sound exactly the same, they obviously can’t be used as substitutes for each other. No catchy memory tricks for this one – you simply need to remember that the apostrophe replaces the a in you are to create you’re.