Don't eat within two hours of bedtime, avoiding big meals and alcohol, which can knock you out, but later wake you up. And nix the spicy or fatty foods, because they can cause heartburn, which interferes with sleep.
If you really want a great night's sleep, turn your bedroom into a true sleep chamber. That means eliminating anything your brain associates with wakefulness. So when you're in bed, don't do things like watch TV, pay the bills or have tense conversations.
In fact, if you worry in bed, think about something calm, or get out of bed and go to another room and take a paper and pend and write down your problems. This subconsciously transfers them from your mind to the paper, relieving stress, so you can go back to bed.
Regular exercise, particularly in the afternoon, can have you sleeping like a baby. So can taking a warm shower or bath before bed.
When you are in the bedroom, lower the thermostat, keep it dark and quiet, and if there are still issues, use a sleep mask and earplugs.
Make sure you go to bed and wake up at the same time everyday, even on weekends. And since nicotine is a stimulant, stop smoking.
If these tips don't work, see your doctor. He or she may refer you to a sleep center, where more serious sleep disorders are identified and treated.