Ocantu,
I wouldn't say that waitresses are a waste of time because they're flirting to get better tips, although it is sometimes the case. But it's pretty easy to spot these kinds of waitresses if you discretely watch how she addresses the rest of her tables. If she sits down and chats with every table with guys, well, you know what she's doing. The reason waitresses are difficult is for a number of other reasons. Some of these are:
1) They get hit on CONSTANTLY during their shift.
2) In the restaurant/ bar industry, all the staff are all over each other like rabbits. I've known a few servers/ bartenders over the years and in a lot of cases, if they've worked there a while, they've probably slept with a few different staff members.
3) Even if a waitress does like you, she may not want to act on it because this workplace may be her main social circle (this industry works really strange hours, so chances are this is usually the case). And she may want to maintain her reputation and doesn't know how her co-workers will perceive her / label her a slut etc.
4) Some restaurants have a policy prohibiting them from fraternizing with customers.
So, I wouldn't say it's impossible to make something happen, just more difficult than your typical girl. Bear in mind, there is no approach here on your part, since she has to talk to you in order to do her job. This means you have to be that much more impressive when you do talk to her. I have successfully done it in the past, and here are some of my pointers:
Get some sort of investment. Obviously, it will be hard to get investment from her. Your best bet if is you can get her to sit at your table for a while. Or better yet, if her shift ends early enough, ask her if she wants to get a drink/food elsewhere. Do not stay at her workplace to avoid the social circle problem. And on top of that, I'm sure she doesn't want to stay late at her work and not get paid for it, would you?
Go to places when it's not busy. It's a lot easier to get her interested and more invested if it's not busy. If you're asking her to sit at your table when she's running around frantically, she'll just get annoyed.
Be discreet. If it comes to the point where it looks like you can get her number, don't pull out your phone. This is her workplace, you need to be very discreet. Ask her to write it down on a receipt when she has a chance. If she doesn't care about discretion, she'll ask for your phone.
Don't be a regular. I've noticed this thing that some waitresses do that is a deceiving form of friend-zone. They may really enjoy your company (you're making her work day go by quicker). She'll ask you to come visit her again at work (she'll tell you her next shifts that week for example). A lot of guys will make the mistake of thinking that that is progress, but it goes against moving quickly and you are investing a lot very early on in doing so. Tell her you're a busy guy and you enjoy spending time with her, but you're probably not gonna be coming back there. If she really likes you, you'll get a number.
Get her off auto-pilot. Waitresses are in even more focused auto-pilot than your typical girl. Sometimes, even things that would get other girls out of auto-pilot won't get a waitress out of it. This is where it is really important to be unique.
Last, don't be a creep. I've known enough waitresses to know they take a lot of crap in the course of their day. Just be suave and charming, and she may end up leaving her workplace with you!
Regards,
-Doc