Try getting late day exposure, stay a little more active than normal late in the day and see if that doesn't help you stay awake longer. I have a designated bedtime that I do not allow myself to go to bed before. I don't go down at the designated bedtime if I am not sleepy either. It is not a good habit to get into. Although, some nights that Colt 45 just hits the spot.
Many people find certain types of music very relaxing.
I say the key is What works best for you. Without being facitious, the best answer for someone who has problems with sleep due to shift work is to get a real job. The best advice I have seen says to have caffeine early in the shift. If possible, be in a darker environment as the night wears on. Very important to have a wind down period before trying to sleep-don't jump right in bed.