71:2 A normal, healthy person should eat a smaller meal at night than he does during the day. This protects one’s health, keeps one from improper thoughts, help one’s dreams to be calm and pleasant – because excessive eating and drinking often leads to weird and disturbing dreams – and doesn’t cause a person to sleep so heavily that he won’t arise at the proper time. Six hours of sleep is enough for a healthy person. (Mishnah Brurah 238:2 says there’s not set measure of sleep; it all depends on the individual.) One should try not to sleep alone in a room, or in a place that is too hot or too cold. (Shaar HaTziyon 239:17 says that the practice is not to be stringent about sleeping alone in a room.)
71:3 A G-d-fearing person, before going to sleep, should examine his day’s activities. If he realizes that he committed some act of wrongdoing, he should express his regret, admit that what he did was wrong, and resolve not to do it again. One should pay particular attention to such sins as flattery, lying, mocking and gossip. One should also resolve to forgive anyone who may have wronged him so that others will not be punished on his account. The Talmud in Shabbos (149b) tells us that a person is not permitted into G-d’s Presence if another is punished on account of him. A person should say three times, “I absolve anyone who may have wronged me.” Afterwards, he should say, “Master of the world, behold I forgive...” (see Talmud Megillah 28a).