Sleep should be viewed as a necessary daily battery charge for your mental and physical functions.  Human battery changing varies from individual to individual and can get quite complicated.  In general sleep for most falls roughly into a range of 7 to 8 plus hours, and there are generalized variations based on culture, geography, and the pace of a given society. For the most part everyone knows whether they sleep well or not, or if they have had a good or bad night of sleep.

Just as good nutrition habits are important so are good sleep habits, and they are related to a large degree. Exercise habits play an equally large role in sleep as well.  Sleep deprivation has long term negative effects tied to both your mental and physical health.  Health and sleep are inseparable.

Some basic rules seem to indicate that having a consistent sleep schedule is good, and going to sleep earlier seems better.  Additional preparation includes avoiding large meals and drinks near bedtime. Avoiding electronics and their glare for a reasonable period- of -time before heading to sleep and turn-off or remove them from the bedroom.  Nothing beats a relaxing, quiet, dark, and appropriate temperature bedroom.  Stress may be a tough one to avoid for many, best you simply resolve to put it on the back burner until morning.   

Naps are another consideration.  Many countries people take brief/reasonable naps, and there are studies that indicate this works as a short-quick battery recharge that seems to bump up performance. In Japan naps are common and they also have a term, karoshi, which is death from lack of sleep, stress, and long work hours. Imagine the diseases you have or hope to never have, they all have greater incidence when there is a lack of sleep. Make your sleep a priority, and a reasonable siesta might be okay.