NEW YORK — One of the best moments of a long, hectic day often comes at the very end, when you fall into bed, pull up the covers and drop off to sleep.

Unless your bedroom is an uninviting mess.

A poorly chosen paint colour you would rather forget, an uncomfortable rug underfoot and the glare of streetlights outside are just some of the problems that can conspire to create a room you would rather avoid — the opposite of an ideal environment for deep sleep.

“Our bedroom environment is probably the most modifiable factor that can influence our sleep health,” said Ms Natalie Dautovich, an assistant professor of psychology at Virginia Commonwealth University and the environmental fellow for the National Sleep Foundation. “There are things we can do to improve the bedroom that will help us to fall asleep more easily, return to sleep when we wake up during the night and stay asleep until our desired wake time.”

Specifically, “the ideal bedroom environment is dark, quiet and cool — very cavelike, in a sense,” Ms Dautovich said.

But by adding comfort and a feeling of security, we can do much better than a cave. For tips on how to design a restful bedroom, we consulted designers and scientists.

CHOOSE CALM COLOURS

When your objective is to create a comforting environment, the bedroom is not the place to experiment with dazzling patterns or bold colours like lime green or fiery orange.

“I like to make bedrooms supercalm,” said Mr Timothy Godbold, an interior designer in Southampton, New York, who favors a crisp palette of whites and light grays with few, if any, pops of bright colour. “My clients tend to be superbusy people who work a lot, so when they go to bed, they want to clear their minds.”

Mr Mark Cunningham, an interior designer in New York, also prefers a tightly controlled colour palette. “A lot of times they’re kind of monochromatic,” he said of the bedrooms he designs. “I think it’s a nice relief — and retreat — to go into a serene bedroom.”

That doesn’t mean light colours are the only option.

Dark colours can be equally inviting, so long as you choose neutrals and stick with them. In one Manhattan apartment, for instance, Mr Cunningham used a palette of dark grays, resulting in a deeply cozy, cocoonlike bedroom.

REFRESH THE WALLS

The easiest way to surround yourself in a calming colour is with a fresh coat of paint. But in a bedroom, many designers instead opt for a soft wallcovering.

For one San Francisco home, Ms Alison Pickart, a Bay Area designer, created a bedroom with walls upholstered in gray silk velvet. “For me, bedrooms always need to feel supercozy, and I always love to layer textures,” she said.

But the look and feeling of velvet isn’t its only asset — it also helps keep the room quiet. “It’s dead silent,” she said, “because of the acoustical quality of the velvet on top of the cotton batting.”

An economical way of achieving a similar effect is to use wallpaper with the look of fabric. In some of her projects, Ms Pickart has used Suede Lounge wallpaper from Phillip Jeffries, which looks and feels like natural suede once it has been installed.

Even patterned wallpaper can work well in a bedroom, as long as the colours aren’t too wild, said Ms Ellie Cullman, a founder of the New York interior design firm Cullman & Kravis Associates. “Sometimes it creates an element of restfulness, because it’s like being enveloped in the pattern,” she said. “It can be very cozy.”

ADDRESS THE FLOOR

An easy way to make a room with wood floors quieter and more inviting is to add carpet.

“We always love a carpet in a bedroom,” said Ms Lee Cavanaugh, a design partner at Cullman & Kravis. “It’s nice to be able to step out of bed and not just feel a cold wood floor.”

The softer the carpet the better, since it’s a place where you’ll often be barefoot. When the budget allows, “we like to use a carpet with silk in it, because that’s really soft,” Ms Cullman said. But there are a number of pleasing options that are less expensive, including rugs made from wool, cotton and other natural fibers.

Usually, designers install a wall-to-wall carpet or a large area rug that extends under the bed and other furniture, leaving a border of exposed wood around the edges of the room.

The choice comes down to the desired look, as well as the layout of the room, Mr Cunningham said. Often, he said, if there is a walk-in closet or dressing room adjacent to the bedroom, “we’ll do wall-to-wall, just so it can run into the closet.”

MAKE IT DARK

“Light is the most dominant cue for our circadian sleep-wake system,” Ms Dautovich said, so controlling the illumination from windows is important.

The easiest way to reduce the light from outside — whether it’s from the moon, an early sunrise, streetlights or the headlights of passing cars — is with blackout shades or curtains that have a blackout lining.

“The way the sun rises at dawn is particularly powerful,” Ms Dautovich said. “The gradual onset of light cues the body to suppress melatonin and start feeling alert. If your desired wake time is after dawn, then blackout curtains can help with that.”

Of course, bedrooms aren’t used solely at night. Most people also want privacy and some light control during the day, without having to make the room completely dark.

Many designers use multiple layers of window coverings that might include blackout shades inside the window and sheer curtains over top.

Cullman & Kravis frequently goes one step further and installs blackout and solar shades inside the top of each window, and then a decorative treatment, like embroidered curtain panels, over the window casing, for a softer appearance.

In bedrooms with many windows, Mr Godbold recommended installing motorised shades that can be raised and lowered with the push of a button (or smartphone tap), from a company like the Shade Store or Hunter Douglas.

“You don’t necessarily have to have electrical wires in your walls” near the window casings, he said. “There are a lot of battery-operated ones that are really good.”

CONTROL THE LIGHTING

In the same way that layers of window coverings provide better control of natural light, layers of light fixtures can help create the right atmosphere at various times of day.

“We are firm believers in lots of layers of light,” said Ms Cavanaugh of Cullman & Kravis. “We like an overhead light fixture, art lights, sconces and lamps.”

Installing numerous fixtures and lamps may also make it easier to support the body’s natural circadian rhythms.

“Don’t try to get everything out of one fixture in the middle of the room, because you’re probably not going to be able to do it,” said Ms Mariana Figueiro, the director of the Lighting Research Center at Rensselaer Polytechnic Institute. “You really need bright light during the day and then dimmer, warmer colours in the evening, because that’s what gives you that robust light-dark pattern that helps maintain entrainment for the circadian system.”

Bedroom light fixtures and lamps should be on dimmers, she said, and bulbs should have a warm colour temperature of about 2,700 kelvin.

That way, all the fixtures can be switched on at full wattage to brightly illuminate the room in the morning, but then the ceiling fixture can be switched off and bedside lamps can be dimmed in the evening.

Also consider having a storage place for electronics like smartphones — inside the drawer of a nightstand, for example — where they won’t disrupt sleep with late-night notifications.

MAKE THE BED

A platform or a four-poster bed? A soft or firm mattress? Many pillows or just a few?

When designing the centerpiece of the bedroom, so much comes down to personal preference and sleep habits. But there are some rules of thumb.

In general, “our mattress height is usually around 24 or 25 inches,” Mr Cunningham said, although some people may like it a few inches lower. To avoid ending up with a bed that’s uncomfortably high, he said, consider how the height of the bed frame, box spring and mattress will add up when shopping for components.

For a reassuring sense of enclosure, Mr Cunningham often uses four-poster beds in his projects. (He has also designed an upholstered model of his own, which he sells through his Manhattan showroom, Marked.)

It’s also possible to create the illusion of a four-poster bed, if you don’t want to splurge for one. In a house in Greenwich, Connecticut, Mr Cunningham installed a ceiling-mounted drapery rail above the bed, with long, sheer curtains that can encircle it and park at the four corners when open.

As for choosing a mattress, Ms Pickart stressed the importance of trying out several mattresses in person to find your preferred comfort level, rather than taking a chance with an online order. “It’s something that you return to every day to recover and prepare for the next day,” she said. “You really have to take your time and find the right thing.”

To finish it off, Mr Godbold usually keeps the bedding simple, topping mattresses with white sheets, a blanket or duvet and a minimum of pillows.

“For me, it’s about having one or two pillows per person, and that’s it,” he said, noting the current trend away from the sumptuously overblown beds of decades past. “It’s not that grandma vibe of having way too many pillows on your bed.” THE NEW YORK TIMES