If you listen to psychologists and therapists, you'll learn that a vast majority of our speech doesn't come out of our mouths. This is one of the reasons that digital communication is so difficult and that producers understood that and created the emoticons. Much of what we learn about what someone is saying comes from the tone in their voice, look in their eye and the position of their body. The last two are called body language.
When I teach persuasion and credibility in the corporate world I often use the 93% perfect and 7% stupid. What is that? Well when you communicate 93% of your credibility comes from your body and voice and 7% from the words you are using!
There are entire studies done of body language, what you can say and how to use it to get exactly what you want. Without getting into the particulars and details, let's use some of this information to telepathically tell the person you're interested in that you ARE interested and open to being approached. Because, let's face it, it is difficult to approach a stranger. Whether you are a man or woman, it can be unnerving to cross a room to talk to a stranger. On the other hand, if you have the impression you are going to get a warm welcome, that trek across the room isn't quite so long.
Your smile is one of the easiest and most natural ways of letting a person know you are approachable. Smile with your lips all the way up to your eyes. When your face shines with joy, it makes you look less defensive. Use eye contact, and then look away smiling. Don't worry, s/he won't think you have gas, he'll think you're flirting.
And the better part is that your smile, the smile you are consciously making happen, tells your subconscious that you are happy, which will flood your brain with endorphins and make you happy, a virtuous circle, which by the way helps other people to feel great too!
Keep your head up and engage with the people around you. Nothing is more difficult or off putting than trying to get the attention of someone engrossed in their phone or tablet. In the same vein, keep other objects from blocking your body from others at the party. Hold your drink in your hand by your side, keep your arms at your side and not crossed, don't cross your legs when seated and don't stand too close to anyone other than the person who interests you.
Angle your body toward the person you're interested in and not away. This is another one of those things that block a person from you. If you are seated, point your feet toward the "target". If you are standing, angle your shoulders toward him or her and turn your head slightly to talk to your friends.
And last, but certainly not least, keep a positive attitude! This comes across in your actions, your eyes, your smile and your laugh. Keep the volume down and the positivity up. The person you have your eye on will be coming across the room before you know it.[:]