LPT: when flirting with a girl in the club instead of asking for her number offer yours.

Many women can feel intimidated and feel awkward or scared to reject a guy asking for her number. If you offer her yours this is less threatening so she can feel more comfortable. If you have trouble dealing with rejection it also helps as you'll rarely get directly put down, but you just may not hear from them which after a few days is much easier. Lastly it eliminates that awkward first text attempt because they can just go, "Hey, it's x from the club the other day, you gave me your number" which flows nicely into conversation.

This isn't entirely gender specific but I think generally this applies to men approaching women.

ETA: probably should have used Woman and not girl in the title.