Thinkstock/ BuzzFeed 1. Use the 90-minute rule. Getty Images/iStockphoto BernardaSv When you sleep, your brain cycles through different stages, each lasting 90 minutes. "You will feel most refreshed when you awake at the end of a 90-minute sleep cycle because you will be closest to your normal waking state," writes Professor Richard Wiseman in Night School.So, starting from when you want to wake up, count back in 90-minute intervals to work out when you should fall asleep. Or let sleepyti.me do it for you. For example, if you want to get up at 7am, try falling asleep at either 11.30pm or 10pm. 2. If you want to nap, do it between 1pm and 3pm. ostrichpillow.com Your circadian rhythm makes you feel alert in the morning, peaking between 7am and 9am, but after 11am your alertness levels start to drop, reaching a low between 1 and 3pm. (Meaning that your mid-afternoon lethargy can't be entirely blamed on a lunchtime burrito.) Use the slump to your advantage and take a quick nap, if you're able to. If you don't have access to a bed, there are pillows you can buy to help you sleep on the go. 3. Drink a coffee before a quick nap. Getty Images/iStockphoto LuminaStock Caffeine takes 20 minutes to get going, so downing an espresso immediately before a short nap will mean it kicks in as you're waking up, making you extra alert. 4. Get some exercise. Getty Images/iStockphoto fatchoi Two and a half hours of moderate aerobic activity or one and a quarter hours of more vigorous activity per week will help you sleep at night. Just don't do it directly before going to sleep. "Exercise can make you all hot and sweaty, and you need time to cool down before heading to bed," writes Wiseman. 5. Avoid bright screens in the few hours before bed. Getty Images Photodisc Research has shown that blue light keeps you awake because it suppresses the production of melatonin. Sadly, that means TVs, computers, and smartphones, as well as providing you with things to do that keep you awake, could actually be stopping you getting to sleep when you want to.If you must work late, dim your phone screen as much as you can and use a program such as f.lux to get rid of that blue glow from your computer screen. You could even go as far as wearing amber-tinted glasses – they've been shown to improve sleep quality and mood. 6. Use neutral sounds to tackle noise pollution. Getty Images Liquidlibrary Even when you're asleep your brain is listening out for sounds that might mean danger. Research has shown that white noise or nature sounds (think waves crashing or rain falling) can drown out annoying noises, like those from rowdy revellers or planes flying overhead.Or you could use Wiseman's specially created track. 7. Wear a pair of warm socks if you're too cold, or stick your feet out of the duvet if you're hot. Getty Images/iStockphoto belchonock Just over 18°C (65°F), and about 65% humidity, is the ideal room temperature for sleeping according to scientists. But make sure you take care of your feet too. According to Wiseman: "Blood flow distributes heat throughout your body, and if you have bad circulation, your extremities will get cold and cause sleeplessness." A pair of socks is an easy solution to that.On the other hand, if it's too warm, sticking your feet out of the duvet will help. "The basic point is to use your feet to regulate body temperature," Wiseman told BuzzFeed. 8. Have a bath just before bed. Getty Images/iStockphoto Anmfoto A bath around bedtime has been shown to increase sleep quality. Scientists don't quite know why, but it might be because it mimics how your body temperature tends to fall slightly just before you fall asleep. According to Wiseman: "Lying in a warm bath artificially raises your body temperature, but when you climb out of the bath this temperature abruptly drops and sends a signal to your body that you are ready for sleep." 9. List your problems and how you might solve them. Getty Images/iStockphoto anyaberkut If you're having trouble sleeping because you're worrying about a problem at work or in your personal life, get your problems out of your head and on to a piece of paper. In one study, published in Behavioral Sleep Medicine, scientists split volunteers into two groups. Both wrote down three problems they had. But one group also wrote down possible solutions, and those people were more relaxed when they went to bed. 10. Eat a small, carb-filled supper before bed. Getty Images/iStockphoto JoeGough "Research shows that you can easily increase your chances of getting a good night’s sleep by eating a small portion (under 200 calories) of food that is rich in carbohydrates," advises Wiseman. Try a slice of toast, or a small bowl of cereal. 11. Introduce something lavender-scented to your bedroom. Getty Images Tay Jnr This one sounds like a myth, but, weirdly, there is research that backs it up. The Wall Street Journal reported a study of 12 people presented at the European Sleep Research Society in Glasgow in 2008, in which lavender oil sprinkled on bedclothes helped participants to drift off easier. A Japanese study from 2012 had similar findings. You could try using a diffuser or lavender-infused bed linen.A word of caution, though: The US National Institutes of Health recommend avoiding the use of lavender if you are pregnant as not enough is known about its effects. 12. Use your bedroom only for sleep (and sex). Getty Images/Wavebreak Media Wavebreakmedia Ltd This is a well-known piece of advice, but might be hard to follow if, for example, you're a student with just one room, or your bedroom is the only place you can get peace and quiet to work in the evening. But you can try to at least keep your bed sacred. 13. If you wake in the night and don't fall back asleep within 20 minutes, get up. Getty Images Todd Warnock Find something to do to distract yourself – but nothing involving bright screens. Many people read, but it's better to do something that uses your hands as well as your brain.And before you start worrying about losing sleep, remember that getting up in the middle of the night used to be perfectly normal. In pre-industrial times, people took a "first" and "second" sleep. Each lasted around four hours and was punctuated by a period of about an hour. "The time between the two periods was used for various activities, including quietly thinking, reading, smoking, praying, chatting, having sex, and sometimes even visiting neighbours," writes Wiseman. 14. Work out how much sleep you actually need every night. Getty Images/iStockphoto DaveRi This will take a couple of weeks, but it'll be worth it. Choose a time you want to get up in the morning (both on weekdays and on weekends). Then force yourself out of bed at that time every day for two weeks. Only go to bed in the evening when you are tired, but don't force yourself to stay up when you're sleepy. Eventually your brain will adjust and make you feel tired in time to get you into bed for the number of hours of sleep you need – and you'll know how many hours that is. Sweet dreams! Tap to play or pause GIF Tap to play or pause GIF lunatic-zombie.tumblr.com Thanks to Richard Wiseman and his book Night School: Wake Up to the Power of Sleep for these tips.