Holiday season, aka the most wonderful time of the year, is here. What’s less than wonderful, though, is the “What do I wear?” panic when faced with an onslaught of confusing party dress codes. To prepare for the round of champagne-fueled festivities ahead, we turned to the experts — and Amal Clooney‘s head-turning style — to figure out exactly what to wear for each occasion.

First, we had to know: How crucial is it to abide by the dress code after you’ve accepted the invite? “For weddings, black ties, and business occasions, do not mess with the dress code. Holiday parties that are social give you more leeway,” answers Lizzie Post, co-host of Awesome Etiquette on American Public Media’s podcast and great-great granddaughter of etiquette icon Emily Post. She also reminds us not to overshadow the host, especially when the event is in celebration of someone specific.

Camille Seydoux, stylist (and sister!) to Spectre‘s Lea Seydoux, agrees. “Feel good, but show some respect. Don’t come in jeans and a baggy T-shirt,” she says. “If you don’t show some respect to the dress code, you’re not going to be invited anymore. It’s always good to be chic, no matter what.”

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With that in mind, below are 8 holiday party dress codes defined by the professionals themselves.

Black Tie

Black tie attire requires tuxedos for men, but for women, it’s all about the hemline, which is why Clooney opted for a floor-length Maison Margiela piece at the 2015 Met Gala (above). “Ninety percent of the time black tie means a formal gown and you should be looking at something that is floor-length,” Post explains, despite today’s preference for knee-length dresses. “We do say a cocktail dress is OK, but it should be very formal. It can’t be just some jersey knit, no-wrinkle type thing. You need to dress it up, especially if you decide to go short.”

Seydoux puts it in layman’s terms: “Black tie means you need to be fancy. You need to have a beautiful long dress, maybe ball gown.” Troy Williams, an L.A.-based event planner who has staged parties for the Academy Awards and Golden Globes, says this dress code gives you the freedom to go long and whip out the good jewelry. “This is your Met Gala, like the top of the dressing chain, the top of the heap,” he says.

Click through the gallery ahead for more tips and inspiration.