I suppose there are many many methods, but this one comes with a money-back guarantee. It will work even on employees who are generally calm and easygoing. Trust me.
First, show up at or slightly after closing time to purchase a book you had special ordered. If necessary, get a friend to go in before you and ask lots of questions so that the employees are distracted into not locking the doors right at closing time, so that you can make your entrance at the appropriate time. This won't do much to accomplish your goals yet, but it will be important later.
Now, be sure not to purchase your book right away. First, ask about another special order you had made that afternoon. You must act very confused. Talk about how you thought it was one title, but now someone has told you this other title. They should both be very common titles, of course. Give them as little information as possible. I wouldn't even give them author names, if I were you. Make it sound like it is the fault of the employees and the bookstore that you don't know which book you want. Rebuff every attempt to help by asking further questions.
Soon you will be able to ask for employee names. Complain about how many people you have talked to, even if it's only been two, and a third to tell you what time the store closes. In fact, you really shouldn't mention that last part. Just call it three. After all, employees should be on call 24/7 so that customers can always talk to the same person. Of course you can't say that, and the employees won't say it sarcastically to you, but at this point, they will be thinking it. See, you're doing well. By now the average employee should be quite upset.
Ask for the manager's name several times. Continue to be confused about which book you want while blaming it on the customer service. Say things like, "So which is it?" and "But she said..." For example, you could expect them to comply with the statements someone else made a couple weeks ago about a book which was probably an entirely different title in any case, which wasn't even special ordered at the time (that last part's important, because it means they won't have a record of it). But now, do this while being easily distracted. Flash from one question and assertion to another. This will be very effective, because it will make it harder for the worker to help you, which will in turn make him or her madder when you take offense at how unhelpful he or she is. Oh, and don't worry -- if your assistant mentions that the store is closing and they don't have time to do your research, you can just explain why it's so important that you have this book. It's a gift, of course. It always is. A short explanation will do. Then you can keep right on talking, ignoring the hour.
It should be at least ten minutes after closing by now. Acknowledge this. Say something like, "I know you're about to close, and not to make you hurry, but..." -- then proceed with talking and talking and talking. Eventually bring it up again, with a comment like, "I know you girls probably want to get home." Continue to talk. You can make your original purchase now, although you should probably ask about the hardback edition's price as well. Something of that nature. Once you've bought it and the person assisting you has miraculously helped you to see that the book already on order for you, is still, in fact, the one you wanted, you can begin to make your farewells; but be sure to be long-winded about it! Be as talkative, needy, and ADD as you possibly can be. Talk about the lotion next to one of the computers, if you have to. Or the mug they keep their pens in.
Congratulations, you win! However, I must warn you -- if you don't want to stop at making them mad and getting them to talk about you behind your back, but want to receive less than excellent service as well, you must do more. I can't help you there. Short of stealing from the store, I don't know how to accomplish that. And I hope I never learn.