Don't start off a conversation by moaning about the location, the food, your friends. No one wants to be landed with a moaning minnie it only drags down their mood and creates negative chemical emissions in both of you. Don't wear overtly sexually revealing outfits unless you are after sex. Again, the clothes you wear say more about you than you might imagine. Many men imagine women are 'up for it' if they reveal masses of flesh.
Surveys show that women tend to reveal more flesh when they are ovulating.
This is a throwback to our roots when it was important to attract a partner to procreate. Nowadays its not so paramount so be careful. Don't brag about your achievements. If you are overly concerned about you your potential flirtee might suspect you will be uncaring and inconsiderate as well as self centred. Don't see buying someone a drink as an investment in their time.