"One great way to ensure you are getting enough deep sleep is to make sure your sleep cycle is consistent," Dr. Alex Tauberg DC, CSCS, CCSP, EMR, tells Bustle. "Your sleep cycle should be the same every day. That is how we are naturally wired."

So choose a bed time and a wake up time, and stick to it. "If you go to bed at the same time and wake up at the same time every day your body will learn the cycle and get used to it," Dr. Tauberg says. "It will be easier to fall asleep and you will be more likely to get a better night's sleep."

One way to train your body, Dr. Tauberg says, is by setting two alarms. Set one for 30 minutes you'd like to be asleep, and as soon as it goes off start getting ready for bed. Then set another alarm for when you need to wake up.

"As your sleep cycle starts to become regulated you will then find that you can wake up at the same time every day," he says, "without even using the morning alarm clock."

Another way to ensure you fall asleep on time, and enter into those deeper stages, is by building up "sleep pressure," or your need for sleep, which you can do by simply being awake.

"Every minute you are awake the body produces a hormone called adenosine," Meistad says. "When enough of it has been built up the brain shuts off wake-promoting areas." And you get sleepy.

To ensure enough sleep pressure builds up, it can help to avoid things like caffeine, which hides adenosine from the brain by blocking its receptors, Meistad says. Switch to water later in the day, to give caffeine time to wear off.

Believe it or not, it can be more difficult to fall into the deeper stages of sleep if you drift off whilst looking at a screen. So you'll want to go ahead and either put your phone or laptop away once evening arrives. Or protect your eyes.

"Screens and light bulbs emit that blue and green light which suppresses melatonin," Bart Wolbers, MS, researcher at Nature Builds Health, tells Bustle. "You need high melatonin levels to sleep quickly, stay asleep, and maximize deep sleep percentages."

Luckily, there are are blue light blocking glasses available, which only let in red light, Wolbers says, so you can still use a screen without impacting melatonin production.

By going outside in the morning and standing in the sunlight, you might notice that you sleep a lot deeper during the night.

"In your brain there's an area called the suprachiasmatic nucleus," Wolbers says. "That brain area registers the time. Light in your environment affects how that time is registered. [...] If bright light enters your eye, a signal is sent to the suprachiasmatic nucleus telling your brain it's daytime."

And that can help your internal clock, or circadian rhythm, stay on course so your body knows when it's time to be awake, and time to be tired.

"Just staying outside for five minutes in the morning sun is sufficient to set the time in your body's clock [...] correctly," he says. "Bright light exposure during the day has been proven to increase deep sleep percentages at night."

It can be pretty tough to enter into the deeper stages of sleep if you're constantly being disturbed by noises in your house, or even outside. You might not remember waking up, but something like a car alarm or loud roommates can stir you, and it can take some time before you settle back down into deep sleep again, Wolbers says.

One way to ensure you stay asleep is by using earplugs, which Wolbers says can block out noise pollution. Or you can use a white noise machine. "Other options are acoustic panels in the bedroom (which reduce noise by about 7 dB), noise blocking curtains, and making sure windows are airtight," he says.

"Although quick naps that last less than an hour can be beneficial, we should mostly skip daytime naps and wait to catch up on sleep during the nighttime," Karin Sun, sleep expert and founder of Crane & Canopy, tells Bustle. "Studies show that extended naps can confuse our internal clock, leaving us wide awake at night when it’s time to sleep."

Napping also decreases your levels of adenosine and causes you to have lighter sleep during the night, Meistad says. So if you can safely stay awake until bed time, that may be your best bet for getting deep sleep.

All of that said, one of the best ways to get deep sleep is to simply go to bed. Because it is possible to try too hard and think too much about sleep, to the point you're lying there wide awake instead.

"The body produces and regulates sleep by itself — sleep only becomes a problem when we try to control it," Martin Reed, a certified clinical sleep health expert, tells Bustle. "As long as we are going to bed at night and falling asleep, our body will produce the exact amount of deep sleep that it needs."

You should set up your room for good sleep, and avoid making mistakes that can keep you up — such as using your phone right before bed. But sometimes all you need to do is drift off and let your body do its thing.