You may feel drowsy initially, but alcohol interferes significantly with the quality of your sleep during the night. Read something non-academic and pleasurable, but not, for example, a gripping mystery. Write in a journal. Take a hot bath 1-2 hours before bedtime. Substitute a warm glass of milk for the alcohol you might drink.
Milk contains an amino acid that fosters sleep.
If you are not asleep in 30 minutes, get out of bed and watch t.v., read or meditate. Remember that it takes a while to develop poor sleep habits, so it will take a while to establish a good sleep routine.