You’ve seen The Big Lebowski a few thousand times, so you know the right rug can really tie a room together. But you still don’t have one.

“Having a rug is super important for grounding a space and making it feel whole,” says Jaime Derringer, founder and executive editor of Design Milk. It also absorbs echoes and feels comfortable under your feet, and so gives your place a warm, “this is not a college dorm” feel, she says.

In terms of your rug’s look, subtle shades and patterns are always safe. “You don’t want a rug that’s competing with other things in the room, so a neutral rug is never a bad thing,” she says. Also, it should be big enough for your stuff to stand on. “Make sure it’s at least a few feet wider than your couch on each side, or it will look like an afterthought,” says Nancy Mitchell, a senior writer for Apartment Therapy.

Now that you’ve got your rug, you’re avoiding one of the most common interior design mistakes guys make. Here are eight more.

Few rooms, especially those in cramped city apartments, are large enough to accommodate a big sectional. “The first thing to keep in mind is proportion,” Derringer says. “You want furniture that fits comfortably in a space and that gives it balance.” For smaller spaces, that means shopping for smaller, spindlier furniture pieces—not those massive couches most guys gravitate toward.

You also want your furniture—chairs, sofas, end tables—to have some consistent proportions. That doesn’t mean they have to match. In fact, it’s better if they don’t, Derringer says. But if you have a compact couch with narrow arms and legs—a good choice for a small apartment—you don’t want to combine that with a chunky leather ottoman or bulky coffee tables.

Before you do any shopping, take some time to measure your room. “Think about how you’re going to move around and use the space,” she says. “Also think about if you’re going to have people over, and where they can sit and interact.”

Avoid the temptation to tape up the same posters you had on your walls in college. “Hang something above your sofa in a real, legit frame,” Mitchell says. “Also, one big piece will look much better than a bunch of teeny tiny ones.” Bonus points if the art or image you go with actually has some meaning for you—as opposed to something you just picked up at IKEA.

“A mattress on a frame looks 100% more grown-up than a mattress on the floor,” Mitchell says. Add a headboard, and you’re really starting to give off that grown-ass man vibe that women find appealing.

Men tend to buy dark furniture and use dark paint. But if you’re living in tight quarters, these choices make the whole space seem smaller and “man cave-ish,” Derringer says. Actually, they do that even if you have a big space. “Try to go lighter with your color choices,” she says.

Light can make or break a room. But many guys have never considered adding to whatever’s built into the walls or ceiling of their pad. “Consider a floor lamp,” Derringer says. “There are so many cool, masculine ones available now.” Swapping out the $10 ceiling fixture for some kind of pendant light is another smart move, she says.

Skipping window treatments might be the number-one design element guys neglect, Derringer says. That’s a shame, because “drapery gives a room warmth and makes a space feel inviting and lived in,” she says. Coordinate with your wall color, or just go with an off-white to play it safe.

Most men can’t wait to mount a new flatscreen when they move into a place. But sorting out all the dangling cables and boxes is a chore they didn’t consider and never deal with. “Get a real TV stand—like one with doors and everything,” Mitchell says. “A massive tangle of wires, consoles, and cable boxes hidden from view will make your room look 100% better.”

You don’t need much to fill out your space. But some nice-looking coasters, a cool blanket, and a plant or two are a few of the little touches you need to complete your space, says Tariq Dixon, co-founder of TRNK, a New York-based men’s home design shop. “These accessories are icing on the cake, and round a place out,” Derringer adds.