The Christmas party at work is cocktail attire and I have no idea what that means. What are some basic guidelines for men's cocktail attire? I have been putting effort into dressing better and buying nicer clothes, but I've never really been a suit and tie person.
I'll try to be really clear and straight-forward about this. Cocktail attire for men is pretty easy - you have a little bit of flexibility, because 'cocktail' just means 'in between formal and semi-formal'. You're probably going to have to wear a suit. If you don't own one, look into renting one for the work party. It's a lot harder to rent a suit than a tux, but you can get exactly what you want for the work event. Or, if you've got some money to spend on a suit, even though you're not really a suit guy, a gray suit with notched lapels (my preference is notched lapels; i think most people look best in them) helps you build looks of all sorts of levels of formality. If you have time and don't plan on imminently losing a lot of weight, get your suit tailored. If you don't, you'll live.
As for what to wear and how to dress yourself:
You might want to do something nice with your hair. Brush it, pomade, whatever your thing is. Clean up your facial hair. Hair is the bow on the parcel that is your suit. If you don't have a 'thing' you do to your hair, don't worry about it.
What kind of suit? You can get away with something that isn't black or midnight blue at a cocktail party, so if you have something that's at least semi-formal but has, like, checks or a pattern or a colour you wouldn't normally wear at work, that's another option. I personally wouldn't want to be the one dressed weird at the christmas party, so I'd suggest a gray suit, plain or striped (candy-cane striped???) tie, work shoes, work belt. Because we haven't gone all the way into 'formal', pocket squares or other jewelry (tie clip, earrings, cuff links) are optional and not called for.
The big 'thing' this winter / holiday season is velvet. It has a warmth and depth to it, as well as the obvious texture, that make it a focal point of any outfit. You might be able to find a velvet blazer that fits. If you wore that with some professional basics (work shirt, work pants, etc), you would be dressed for the cocktail party but also dressed 'fashionably'. If you don't want to buy a velvet blazer for this one party, don't - you'll only have a few more chances to wear it until it goes to the back of the closet for next year's christmas party. If you want, go to Zara or somewhere else with a really good returns policy, and bring it back later that week.
A side-note on work party etiquette: most agony aunts avoid getting tipsy, let alone drunk, at any kind of work fundraiser or event. It's still all coworkers, and you don't want to be dumb in front of them. You don't want to not
drink, but sip, don't chug. A highball beats a beer, and a whiskey beats a highball if you like whiskey. Try not to talk about work for longer than a sentence or two (nobody else wants to either!!!). Have a good time, wish your boss a merry christmas, and get drunk at home.
Hope this helps!