Ok, you've finally completed step 1 of how to talk to girls: the approach.
Now, you're standing there like a deer in the headlights, with about as many pick up lines as that same deer would have in this situation.
Don't worry, you are going to get some actual examples of the best pick up lines, but, of course, first comes the obligatory "it's not what you say, but how you say it" speech that you've probably read a thousand times.
The reason it always accompanies these types of articles is simple: It's true! No matter what magical, mesmerizing line you come up with, a woman's ears can translate the message in two different ways.
If you're cool, calm, and confident, then it could knock her off her feet and leave her begging to hear more.
Or, if you're nervous, fidgety, and unsure, the exact same words in the exact same order could produce a sentence that sends her searching for a police officer, her giant boyfriend, or another girl with whom she can laugh at your shame and humiliation.
But, in the very beginning of learning how to talk to girls, there really may be a need for some training wheels, so to speak.
At least, pick up lines will provide you with something to say as you learn your way around the wonderful world of social interaction, but just don't expect them to do much more.
Enough with the Lecture, Give Me the Best Pick Up Lines! Your impatience will not serve you well in your journey for that which you seek, young grasshopper, but, as you wish:

1. Hi, my name's John.
   Yes, it really can be that simple.
   Ask any girl, and she'll tell you sometimes all she wants is for you to simply initiate the conversation.
   However, please insert your own name, genius!
2. "I'm just about to leave, but I had to come introduce myself.
   "
3. "Write your number down, and I'll give you a call this week.
   "
4. "I want your opinion on something my friend and I were discussing...
   (insert interesting topic here).
   "
5. "Is there any extra room in those jeans, because I'd love to get inside your pants.
   " (Hopefully, you realize this one is a joke.
   Although, if used in the right sarcastic context with the right girl, it could actually work.
   )

Remember, these are only your training wheels to use while you get more comfortable approaching and talking to girls.
These pickup lines will not produce magical results overnight, and neither will any others.
But, as hard as it is to believe, as you continue forcing yourself through the process, your mind and mannerisms will adapt, until you can say just about anything and still get the girl.