An estimated three out of four American adults have trouble sleeping peacefully. We have trouble nodding off or we toss and turn, and we wake up cranky. Fortunately, there are some simple solutions. Try these tips and see if they help you get more satisfying slumber.

Change your sleeping surface

Remember squirming on those hard schoolroom chairs, waiting for the bell to ring? You were restless for a reason: That hard wooden chair put a lot of pressure on your behind. A mattress that's too firm can have the same effect: Lying on the stiff surface puts pressure on your shoulders and hips. Studies show that too much pressure can cut off your circulation at night, making you toss and turn and keeping you from getting deep, restful sleep.
Sleep experts say that your mattress needs to have the right balance between support and comfort. It should "give" more where you need it, typically under your hips and shoulders, but support you in other places so that your spine is relatively straight. To find out if your mattress is too stiff, try laying a spare comforter under your top sheet tonight. If the extra padding helps you sleep more comfortably, look for a "mattress pillow" -- any inch or two of padding that goes on top of your mattress. It can be anything from a simple $35 foam pad to a $200 down featherbed.

Choose the right pillow

Your pillow cradles your head all night, working with your mattress to keep your neck and body properly aligned. If you're always adjusting your pillow or if you wake up with a stiff neck, it might be time to check if you're using the right kind of pillow.
Experts say that side sleepers generally need higher and firmer pillows than back sleepers. If you're a side sleeper, make sure your pillow won't compress much when you're sleeping. Most polyester fills will flatten noticeably in a few months, but synthetic and latex foams stay springy for years. If you sleep on your stomach, try a down pillow that you can squash flat. If that isn't comfortable, you might be better off without a pillow. Also, if you wake up with a headache or sniffles, try switching materials. You may be allergic to down feathers or sensitive to synthetics.

Dim the lights

Your body's internal clock takes its cues from light, and if it isn't in synch with your daily schedule the quality of your sleep suffers. If you have trouble falling asleep at night, for instance, you might want to start dimming the lights around your house at least an hour before bedtime. The reason: Light prevents the pineal gland in your brain from producing melatonin, a hormone that regulates your internal or circadian rhythms and helps make you sleepy. That's why you feel more awake on bright, sunny days than on overcast ones. Dimming the lights earlier will help trigger your body to produce more melatonin by bedtime, helping you fall asleep faster.
Similarly, experts say, if you tend to wake up in the middle of the night and have a hard time getting back to sleep, your daily cycle may be peaking too early. Try avoiding bright sunlight in the early morning and getting some extra rays late in the afternoon to shift your cycle forward.

Cool down

You may not realize it, but your body's core temperature varies by as much as 2 degrees F throughout the day, peaking around 2:00 to 6:00 in the afternoon and dipping to its lowest point between midnight and four o'clock in the morning. Sleep researchers say that when your temperature starts dropping for the night, it helps you fall asleep more easily. Many people have trouble reaching this lower temperature at night, especially as they get older. One solution: Take a hot bath or shower. It relaxes tense muscles, and when the water evaporates off your skin you actually cool down. Exercising at least four hours before bedtime can have the same effect: You heat up after you exercise, but a few hours later you cool down to lower than your average temperature.
The temperature surrounding your body is important, too. If your room or bed feels too hot or cool, you may have trouble falling and staying asleep. Turn your thermostat down to 65 degrees F or lower; wear light, loose clothing; and use layers of blankets, so you can control how warm you feel in bed.