The point of
flirting,
IMHO, is to let someone whom you are
attracted to know that you are
attracted to them, and have some fun at the same time. The main point to this is that it is not
threatening and you are giving them a
complement.
You cannot flirt if you have no confidence in yourself. Perhaps you need to speak more freely with members of the $targetSex gender, so that you can realise that they are as confused as you are about the whole issue of people to people relationships.
If someone flirts with you, its a complement. If you're not interested, accept it but dont flirt back.
It is considered bad form to flirt when you are with your significant other, or if they are likely to find out - they may think you are shopping around for a new significant other, even if you are simply keeping your knives sharp.
Flirting is fun. always remember that. It helps boost people's confidence as well.
Flirting can also progress into more serious relationships, if the attraction is mutual.