When I was interested in learning about the numerouse recipes for drinks, I
befriended a bartender who had about 40 years of experience. The bar he
worked at was frequented by an older crowd, so he would tell me the most
popular drinks that they ordered, Brandy alexanders, etc. He also recomended
the Library and bookstores.
I also befriended, a young bartender named rose, the bar was frequented by a
young crowd, she told me how to make margaritas, toasted almonds, melon balls,
B52s etc. but she said there were always new drink recipes to learn.
If you don't have time though to go to a bar, then get some books at the
library and book store. In fact the school should be able to recommend some
books for you to get started.
One of the best sources of course is the internet.
Hope this helps.