Don't make the same mistake I did!
I had read on various pages that waitresses, bartenders etc. get hit on all the time,
so it's usually better to let her get comfortable with you over a number of meetings.
So in other words they are saying don't ask for her number the first time you meet her.
But there is a balance to that theory which I found-out the hard-way!
I've been flirting with this very sweet and very cute girl who worked at a local bagel shop. This morning I was fully intending to ask her out. When I went to the shop, I didn't see her. So I asked one of the other girls when she is scheduled to work again?
To my horror, I was told that she had recently left the job to work as a receptionist elsewhere! Now I'm kicking myself for dragging it on for too long!
So learn from my mistake and don't wait too long to ask her out!

On a monday, you can say something like "How was your weekend? Did you do anything fun?" If she says she did nothing but sit at home alone and play "SimCity"
Then you get some insight into if she has a bf and what she likes doing for fun. Also, just joke around about anything! Don't take it too serious. If you're having fun talking with her, she'll enjoy talking with you!
Practice chatting-up &/or flirting with lots of women. This help to make you more confident doing it. Lastly, don't put all your eggs in one basket. She's a girl you're working on, but you should always have other girls you're working on, so if one doesn't pan-out, it's never the end of the world.
Like the girl I waited too long for, even though it sucks that I'll probably never see her again, I am always working on several ladies, so it's not the end of the world for me that she didn't pan-out due to my mistake. I'll just learn from it and move-on the the next ones!

That's why practicing is a really good way to get more confident.
When I say "practicing", I mean just strike up a convo with any chick just for the
sake of having a fun convo. With no expectations beyond that.
If you're thinking to yourself that this is just practice, nothing more.
Then you'll realize it doesn't matter what the outcome is.
It's just having fun talking to new people. The more you do it, the more comfortable you'll get with it. Then after a few practice sessions, as you get more comfortable, take little chances and try actually flirting a little bit. Build it up from there. Some people are busy and have things on their mind so they don't wanna talk much. Don't take it personally, just remind yourself that it's not your fault, it's their issue. Then some girls you'll be able to tell that they are enjoying chatting with you! Those are the ones that you try to move it forward with.
If you make a mistake or even crash and burn. It's no big deal, because it's just "practice"! Just learn from your mistake and practice on the next chick you run into.
Since you're in college and surrounded by girls all the time, it's the perfect situation and opportunity to practice on them!
If you get the cold shoulder, just remember that women like what they like oftentimes for no good reason. I've been turned down by average looking chicks and I've been layed by totally gorgeous chicks(even though I'm not the best looking guy!). Some girls have a certain look they like. With other girls, it doesn't matter what you look like. Some girls will only date guys their age. Some girls have a thing for older men. So if a girl blows you off.
Just say to yourself "Next!" and practice on the next girl. No worries mate!