If you've been chatting for a little bit, pause the conversation and look into her eyes. Say, “Hey, I really like you,” then wait for her reaction. You could also say something like, “So, I've been meaning to tell you: I think I have feelings for you.”
Regarding romantic relationships, it can be difficult to know whether or not someone is interested in you. This can be especially true for girls, who may try to hide their feelings or play hard to get them. Besides, not everyone will reveal their cards at once at the initial stage of a relationship.
Touch their arm or knee when you laugh at their jokes. Notice when their glass is empty, and always offer to fill it up or get them another. Make eye contact from across the room at parties; smile. If you get an inside joke going between just the two of you, work it into conversation often.
“Making eye contact and holding it just a few seconds longer than a casual glance causes him to take notice of you and start to wonder what you may have meant by that,” says Lieberman. “It's the cool 'silent flirt' that can make him want to know more.”
Smile. It's important that you feel and represent yourself as being friendly, open, and approachable. You want to convey that you are confident, comfortable, and have a kind personality. Use your smile to break the ice and make a good impression on the girl that you like.
That depends a lot on what's comfortable for both of you. She might enjoy gentle caresses on her face and neck, or she might enjoy back rubs or having your arms around her waist. Experiment with different touches and ask what she likes or dislikes.
Flirting is all about human connection, and a really simple way to connect is to mention casually something you might already know about them—be it from their dating profile or a prior conversation. “Start the conversation off with something specific and interesting, and speak to what you already know about them…
This can mean buying a drink in a social setting, freely giving compliments, side arm hugs or other non-sexual touches, a platonic friendship. The term “harmless” is only applicable if you are willing to disclose this behavior (without shame or concern) to your partner.
"They make a lot of eye contact. They are interested in what you have to say and ask you lots of questions. They laugh at your jokes, even the lame ones. They initiate physical contact.
In his book he examines five key styles: polite, playful, sincere, and traditional. Take the quiz here to see which one you are. There is no right or wrong way to flirt, but according to author Jeffrey Hall there are five different styles.