Limit caffeine intake: Those who take caffeine find it harder to fall asleep. Even a single cup of coffee taken in the morning may lead to sleeplessness at night. Caffeine tends to inhibit the effects of adenosine, a neurotransmitter that is believed to promote sleep. Caffeine also interrupts sleep as it increases the need to urinate during the night.

Caffeine withdrawal tends to lead to headache, irritability, and fatigue. Therefore, it seems wiser to cut back gradually. Those who can’t or are not willing to give up caffeine should avoid it after 2 p.m., or noon, particularly if they are caffeine-sensitive.

1. Quit the habit of smoking or chewing tobacco: Nicotine is a known stimulant of the central nervous system, and can cause insomnia. If you continue to use tobacco, try to avoid smoking or chewing it for at least one to two hours prior to bedtime.
2. Limit alcohol intake: Alcohol tends to depress the nervous system. As a result, a nightcap may appear to help some people fall asleep. Alcohol suppresses REM sleep, and the soporific effects tend to disappear after a few hours. Alcohol can worsen snoring and other sleep-related breathing problems.

[Source: Harvard Health]