Proximity is all about creating the chemistry. So hinting at what could happen using your body rather than any sort of physical contact or speaking is a really important flirting skill.
Using proximity as a technique is very similar to using your body language to flirt with a guy but way more delicate...
Position yourself too close and you run the risk of coming across overbearing, but too far away and you can lose any chance of connection.
When you first start to talk to a guy try to stand a few feet away, make him aware of your body but don't be all over him. Then once the conversation has gotten going, you can start to use a few other techniques to make sure he's all yours.