According to Ayurveda Night time is best suited for human beings to sleep because night time is predominant with Thamas. Sleeplessness should be treated according to the condition and symptom of Patient.
Main thing that should be corrected for a patient with sleeplessness is his daily routine because he should have his food, drink, bath, exercise at proper time and should avoid day sleep.
Patients who are affected with Sleeplessness due to mental tension, fear, anger, anxiety should be made free from such things through Sathvavachaya Chikitsa.
Manasamitra Vataka is an excellent drug of choice for those who suffers from mental illness and resultant sleeplessness.
Another thing that should be kept in mind is that aggravation of other doshas except Kapha dosha can affect sleep.
For this treatment should be done to reduce the aggravated dosha by identifying the symptoms for example if Patient is affected with excessive hotness in the body during night time, it must be a resulted from pitta aggravation and in such case pitta dosha is to be eliminated out by Shodhana, Use of Snehana(Oil), Thalam, Thalapodichil etc can win Vata dosha and it help to give coldness to the body which will aggravate kapha dosha and there by provide good sleep by giving a heaviness to the body.
Use of Milk before sleeping is also excellent to get sleep.
Reading books etc is also a good idea to get sleep.