Flirting can be described as being "casual conversation with a romantic spark" and it is a learnable skill.
Here are the usual tips:
Ask her specific, open-ended questions; these demonstrate that you're interested specifically in her as a person and also provide an opportunity for the discussion to take a romantic turn.
Look for humor in what the girl you're flirting with is saying and let yourself laugh at her jokes if you find them funny.
Try to look your best, and use good posture and eye contact.
Don't follow people around or act needy.
Don't be insincere.
Let's examine the topic of rejection. The key thing to understand about rejection seems to be that "everybody gets rejected once in a while." If you never risk rejection, it's likely your social life will end up being very dull. The range of tastes in body type and personality type is enormous; something that you think is a liability is for some people almost certainly a turn-on.
How to tell if she is interested in you? The following are the possible clues:
If she is acting more flirtatious toward you than toward other people at the same event.
If her friends are paying attention to you when she isn't around (often a clue that this person talked to his or her friends about you).
If she is smiling while listening to you, and seems to be listening especially "actively."
There's a lot of crossover between good listening skills and good flirting skills, but there are also clear differences. For example, if you're in a job interview you're obviously going to be listening "actively," but nobody is going to confuse this with flirting. It's the "romantic spark" aspect of flirting that distinguishes it from standard "good listening."
Looking into someone's eyes just a little longer than would ordinarily be considered customary or comfortable seems to be a common element of the flirting process.
The importance of giving sincere complements was mentioned more than once. Going along with the idea of flirting being a learnable skill, a good way to practice flirting is to do it a little bit every day, perhaps with friends or waitresses.
Social networks usually expand by cultivating friendships which are serious enough for your new friends to introduce you to their friends. For this reason, activities that allow prolonged contact with other people are valuable. Political action groups or volunteer groups or special interest/hobby groups are especially worthwhile because you get a chance to meet folks in a more prolonged and sincere context, because you already have a shared interest, and because if nothing good flirting-wise comes out of it at least you either learned more about your hobby or did some good for your community.
So, you can try to enhance your flirting techniques by incorporating these little tricks:
Use flattery and compliments
Make immediate, direct eye contact
Repeat the girl's name, later on, together create nicknames
Let her speak, listen and pay attention
Whisper
Be kind and communicate with other people in her community
Limit the amount of time you flirt and leave her wanting more of you
Here are a few eye contact methods to experiment with: