Flirting starts with not being attached to any outcome. You want to go into this with the mindset of having fun meeting someone new and interesting in the real world. And if it goes somewhere, great. If it doesn't, don't get discouraged. Instead, think of it as having had the opportunity to practice a new dating skill.
Even though your old clothes may still fit, revise your clothes closet, hair color/style, buy a new trench/raincoat. This is about reflecting who you are inside and allowing that to show to the world and other people around you. Let the world see how amazing you are on the outside and your amazing character will do the rest.