I think the first and most important thing to accomplish is a qualitative change in social relationships. This can be related to work relationships, marriage or friends. The best thing that can be effective, is make order in our personal private sphere. If something is going wrong, it is easy to fall into compulsive, racing thoughts before going to sleep, that would debilitate the ability to fall asleep normally.
Second, if you drink too much coffee or take other stimulants it may affect quality of sleep. In case of smokers there's a reduced quality of sleep, since the demand for oxygen is increased as well as increased energy consumption because of higher carbon-monoxide levels. Additionally, caffeine disturbs the circadian rhythm delaying it thus having fewer REM phases. If taken before 6 pm, there would not be any problem
Eating around 7 pm is also a good option, since increase in blood sugar levels and the parasympathetic activity of digestion is the major phenomena that helps to prepare yourself for a good sleep in a range of two hours.
I strongly believe that anxiolytics with sedative or slight hypnotic effects could act as very good relaxants, xanax for example is a good and not really expensive choice.
Above all, exercise is the best option, however it hasn't to be taken as the latest way. It also depends on the quality, the type of exercise and the time spent doing it.