Beside and besides, an easy one...

The difference between the usage of “beside” and besides” is a good thing to get clear on, as it’s an easy one to learn, but an easy one to get fuzzy on as well. 

“Beside” is a pronoun. It is a location for one thing relative to another thing, whether or not that thing can be touched. The nightstand is beside the bed and a good idea lives beside a bad one.

“Besides” means “in addition to,” and in that usage, it is also a preposition: “Besides earning millions in playing contracts, popular athletes earn massive promotional fees as well.” It also serves almost as an antonym to “beside” in the sense of “apart from.” "Besides" also has a linking adverbial function as well when you say something like, “Grammar tiffs are no fun. Besides, you have better things to do.”

It's "Happy New Year," not "Happy New Years."

You wish people a Happy New Year, not a Happy New Years. It is neither plural nor possessive and earns no letter "s," with or without apostrophe. You hope people have a good time on New Year’s Eve, and also on New Year’s Day, but when saying, "Happy New Year," such well wishing expresses your hope for an entire year’s worth of good fortune. There are a few possessive holidays, and they include Valentine’s Day, Mother’s and Father’s Day, and if you’re a fan of Henry V, St. Crispin’s Day. On a related note, Presidents’ Day is plural possessive and Veterans Day is plural. As to the capitalization of "Happy New Year," convention and AP hold that all three letters should be capitalized.