A bath is ideal, but a shower is still effective. The hot water helps to soothe and relax your body, while you visualise the stresses of the day washing away from you. The other benefit is that after you dry off, your body temperature will drop slightly, which sends a signal to the brain to produce more melatonin, for a deeper, more restful sleep.
Personal preference plays a role, but as a guideline soft cotton is nice for summer, while flannel is cosy for winter.
Classical or chill out, ambient or reggae, pick a soothing genre that sings to your soul.
Preferably nothing work-related or to do with study. Reading as a relaxation exercise requires something more escapist, like a crime or romance novel.
While vigorous exercise is not a good idea before bed, stretching can help ease tight muscles before settling down to sleep.
Add 1/8 of a teaspoon of ground nutmeg to a cup of warm milk. Nutmeg works to soothe the nervous system, while milk promotes the release of tryptophan, an amino acid that helps with sleep.
Try and leave the stresses of the day behind you before you go to bed. As you lie down to sleep, think of three things that went right during the day, so you can finish it off on a positive note.