The linked article below has some solid tips.I especially like #3 about bringing something for your host, but nothing that’s a burden. I’ve been guilty of bringing flowers without a vase before and realized my mistake as I saw the busy host scrambling to find a vase for them. It’s a high-maintenance gift.
Alcohol, on the other hand, is always easy and appreciated. If it’s a good friend, give them an unusual item, like St. Germaine elderflower liqueur, which mixes surprisingly well with most liquors, or a twist on a classic, like a honey bourbon, instead of the standard wine.
And champagne is always fun.
Photo source: Modern Party Etiquette for Hosts and Guests.
It's good etiquette to share what you like!