I’m preparing for the height of the wedding season and have been aggressively reviewing the dress codes for each event that I plan to attend. Choosing which dress I’ll wear for which occasion is a big decision for me and I want to get it right. In my own personal research, I came across a lot of “dos” but the “don’ts” were far and few between. Yet we’ve all been to weddings where one or two people didn’t quite dress the part.

I decided that I should ask a bride what would be considered inappropriate on their special day and my mind immediately went to my colleague, Kat Collings, who is currently weeks away from her very own fairytale wedding in France. She let me in on her dress code: “The dress code of my upcoming wedding is ‘fun and formal.’ For me, I found formal to be a nice middle ground between cocktail and black tie, where the vibe doesn’t have to feel too stuffy and red carpet-like, but also people know not to go too casual. I added the ‘fun’ part to the dress code so people feel encouraged to wear color, prints, and have an ease to their look that I think will mesh well with the setting of South of France in the summer.”

With the excitement of seeing how fun her guests dress for the big day ahead, there are still a few no-nos that Kat shared with me. She has been a guest at many weddings in the past and her observations led her to the four things she would not like to see at her wedding. Keep scrolling to make sure you don’t make these fashion mistakes.

“There are all types of weddings, but for most, I would say avoid ‘club’ type dresses. There is usually a wide range of ages present, and it’s a generalization, but sometimes older folks can be a bit more conservative, so best not to draw judgy glances from grandma. If you’re looking for something on the more alluring side, pick an outfit that has one area that’s a bit more revealing. For example, a maxi dress with cutouts rather than a super-short mini with cutouts.”—Collings

A leg slit is a great first example.

Subtle side cutouts are next on the list.

If the dress code allows you to show some stomach, this may just be the look for you.

Emphasize the bust with a corset top to get the ultimate princesscore look.

Every detail on this dress is perfection.

Love at first sight.

Here’s a tutorial on how to become the real-life version of the dancing emoji.

“One thing I’ve seen before is guests who nail the dress code with their clothing, but neglect to level up their accessories too. Picture a person in a cocktail dress with a daytime, more office-appropriate handbag. Each element of your outfit should all be speaking the same language if you will. I know since dressy occasions aren’t as frequent, not everyone has a lot of accessory options, but there are affordable picks aplenty.”—Collings

Wearing heels sounds nice but don’t be afraid to opt-out and go for a pair of flats. Being able to dance the night away is worth it.

You’re going to want a good clutch by your side.

If you do choose heels, you can count on a comfortable pair that has a block heel.

I say be bold with your jewelry.

I’m so here for this.

Greek goddess behavior.

You can’t go wrong with a pastel.

“In general, more dressy materials like silk or chiffon are preferred for weddings over casual fabrics like jersey and cotton. I always figure it’s better to look a little overdressed than under. There are always exceptions to the rule, but if you go for a more daytime fabric, look for other elements that heighten the formal factor, such as beading, appliqués, and bringing it with your accessories.” —Collings

Oh so pretty in pink.

This is simply gorgeous.

Just wow.

You’ll turn heads in this number.

The perfect dress for a wedding that’s in a castle.

She’s everything.

The more extra the better.

“Denim is almost always a no-go for weddings. If pants are more your thing, consider a pair of dressy trousers or a jumpsuit instead. You’ll be comfortable, but still, dress code compliant.” —Collings

And suddenly, I’m a pantsuit girl.

Such an easy ensemble to throw on for the big day.

I’m here for this.

I never saw an Oscar de la Renta look that I did not like.

She’s pretty.

Up Next: My Friends Always Ask Me What to Wear to Weddings—I Tell Them This