The first step to falling asleep faster is to determine why you can't fall asleep. Are you stressed about work, relationships, or financial problems? Do you drink caffeine too close to bedtime? These are a few common reasons for difficulty drifting off (via Risk Management and Healthcare Policy and Baylor College of Medicine). Other biggies are using electronics shortly before bedtime, watching TV in bed, and having a bedroom that isn't conducive to sleep — either because it's too warm, not dark enough, or your bed is uncomfortable (via CDC).
Many health conditions can make falling asleep difficult. According to the Mayo Clinic, these include diabetes, asthma, heart disease, overactive thyroid, Parkinson's disease, cancer, gastroesophageal reflux disease (GERD), chronic pain, and cancer. Mental health disorders, such as anxiety and post-traumatic stress disorder, can make it difficult to drift off. Diagnosed sleep disorders, including sleep apnea and restless leg syndrome, are obvious culprits. And medications, including some depression, asthma, and heart disease medications, can also interfere with getting to sleep quickly.
Whatever the cause of your late nights, using relaxation techniques such as breathing exercises can help. Keep in mind, it's not a substitute for medical care in the case of a health condition, but it can be an effective adjunct treatment.