Well, the first thing would be
sleep hygiene.
1) comfortable dark room kept fairly
cold and with noise abatement.
2) going to bed at a set time and not associating the bed with activities that keep one up (TV, work,etc.)
but,most importantly, not associating the bed with activities that keep one awake like being awake!
so, if not sleepy get out of bed.
Finally, there are a lot of different things that might make someone sleepy and help. It is not possible to predict ahead of time, but exercise, eathing, reading, showers ight be helpfu l or not good at all depending on the person.