Walk tall. As you approach look ahead, not down, and square your shoulders. Walk with an even pace with slight bounce, tilt pelvis forwards, hold your head high, half smile, and look at other people. You'll feel more involved in the world by seeing what's going on around you, not to mention look more confident. All will get you noticed and to first base!
Make up a (flattering) nickname. It makes them feel special because it means you've noticed something unusual about them. It also instantly puts things on a more personal level, the same effect as remembering to mention their name.
Play mum. Everyone likes being taken care of-- particularly if the person coming to their aid happens to be captivatingly sexy! To "mother" them, notice when they need things (a fresh drink, fresh air, a jacket, the time...)
Play it personal. If you want to move things beyond boring chit-chat, volunteer something personal about yourself. The more you open up, the more likely they are to follow.
Be happy. Unless you've got self-deprecating humour routine down to pat, few of us get away with being constantly grumpy. Who would you rather hang around with? A depressed, unhappy moaner or a funny, optimistic, who makes life seem bright and full of promise?
Whispers also work when you're already chatting to the person. Once you've both warmed up, lean forwards and whisper into their ear. It could be conspiratorial ("I don't know about you, but I'm not convinced about the painting") or a compliment (You're very funny by the way".) Then simply pull back, smile, and continue the conversation.
An eye flash. If a man is looking at a woman and their eyes lock, she will often raise her upper eyelids slightly and rapidly. It's a subtle eye-opening movement which says to him, "Yes, it is definitely you I'm looking at."
Can't take my eyes off you. When we're attracted, we really do have difficulty dragging our eyes away. The person stops talking, someone else starts--and we're still gazing adoringly even though they're silent. Do it deliberately for startling effect. Keep your eyes on theirs for a slow count of five during that silence that follows after you, or they, stop talking.
Fake "bedroom eyes". These are essentially eyes with big pupils (they dilate when they like what they see) and lots of moisture (tears pool when we're excited by someone). Get the look by holding your eyes extra-wide, trying not to blink until tears form, then shutting them for a few seconds to block out light (another way to alter pupil size). When you reopen, voila! You'll have shiny eyes with lots of pupil action!