I know that it's a little late to share tips for holiday parties, but I think that you could apply some of these to parties any time of the year. You also may have a few straggling holiday parties left! My first tip is to dress for the type of party you're going to. For example, if you're going somewhere where you'll be dancing, make sure that you wear fairly comfortable shoes.
This is one of my favourite dresses for holiday parties. It's comfortable and casual, which leads me to my second point: wear something that you're comfortable in. If you're not comfortable in it, than you'll be focusing on being uncomfortable instead having fun at the party. Make sure that you've worn your outfit before, you know if it gets more uncomfortable as time wears on.
This relates to my second point, but make sure that you love what you're wearing. If you don't, what's the point of wearing it? This necklace is actually my mom's, I've loved it and admired it for as long as I can remember. You can try to incorporate a piece like that into your outfit, it can make it a little bit more special.
The Black Tux also has a very helpful guide for dressing for Holiday Parties. I'm not very good at the technical aspects of dressing for parties, so I thought that sharing this may help some of you. But overall, I think that the bottom line of dressing for any party is to wear an outfit that makes you feel amazing. You can check out The Black Tux tuxedo and suit rentals here.