“I love placing a mirror above the fireplace—I even have this in my own family room,” says Kathy Kuo, founder and CEO of Kathy Kuo Home. “I find that this not only adds interest and can open up the room but you can also utilize the mantle for additional accents.” That being said, you’ll want to consider a handful of design rules and practical tips before hastily hanging the first mirror you find over your fireplace. Whether you’re hoping to hang a cluster of smaller mirrors or you want to ensure the one mirror you do hang looks like it was made for the space, a few simple tips will ensure you get it right on the first go. Below, we spoke to three interior design experts—who are all advocates for putting a mirror over the fireplace—to get their best tips and insights on exactly how to get it right from both a design and practical perspective. Here’s what you’ll want to keep in mind.

Try to Find a Mirror 2/3 the Size of Your Mantel

You might be tempted to hang a mirror you’ve had kicking around the house or something you picked up on Facebook Marketplace, but you’ll want to make sure you get the size right before drilling a single hole in your wall. “The main thing to remember when placing a mirror over the fireplace is that, no matter the shape of the mirror you choose to go with, the width should at least be 2/3 of the fireplace mantel,” explains Kuo. Otherwise your mirror might look like it’s drowning in the dead space around its perimeter.

Avoid Small Mirrors—For the Most Part

“I would also strongly suggest avoiding small mirrors (less than 30 inches) if you can,” says Kuo. “Small mirrors should only be used if you are trying to layer, leaning it against the wall instead of hanging it, or if there are sconces on each side that limits the wall space.” Small mirrors can also work in the form of a mirror gallery wall; a collection of sunburst-style mirrors or similar options with ornate frames can easily transform a fireplace space just as efficiently.

Consider Layering Your Mirror

If you’re really enamored by a smaller mirror and don’t want to miss the opportunity of displaying it front and center above your fireplace, you might still be able to do so. According to Kuo, a visual frame for a smaller mirror can easily be created by layering decorative accessories in the center or adding surrounding candles at varying heights along the sides of the mantle to help balance out the space.

Don’t Hang It Too Low (Or Too High)

“My number one rule to follow is to choose a mirror that is large enough to fill the vertical space,” says Megan Dufresne, ASID, principal designer at MC Design. “My rule of thumb is to have the bottom of the mirror between 4 to 6 inches above the mantle and I like to leave a foot of space between the top of the mirror and the ceiling,” she explains. If a mirror is hung too high, on the other hand, Dufresne suggests adding plants on either side of the mirror to help fill the gaps and create the illusion of being hung lower than it is.

Double-Check the Mirror’s Reflection

“I’ve used mirrors over fireplaces—hanging or leaning—but you do want to be careful that the reflection when walking into the room is appealing,” says Susan Peters, designer and owner at 9108 designs. ”For instance, you don’t want to be walking into the room with a mirror that is reflecting a less-than-perfect set of bookshelves or a TV screen.” According to Peters, when a mirror is hung in a prominent place facing you when you are walking into the room, a simple, non-cluttered reflection would be best.  This should be considered in living rooms, dining rooms, and such.