It's important to realize that some people are naturally more touchy-feely than others, so you have to pay attention to how the individual interacts with other people to evaluate intentions.

You shouldn't assume that everyone who smiles at you is flirting with you.

However, you can tell a lot about a person's intentions toward you and interest in you from the manner in which he or she smiles when interacting with you.

It may be a smile of friendship, but it can also indicate romantic interest.

The first thing to look for when evaluating whether or not a smile indicates flirting is the person's eyes. If you notice a sparkle in the person's eyes, watch for other flirting behaviors paired with the smile to help you figure out if more than just friendship might be motivating the gleam in the person's eye.

If you respond in like fashion by initiating casual contact of your own, your behavior lets the person know that you recognize and reciprocate the potential interest, and may be interested in getting to know him better. When someone makes an effort to make you smile or laugh, they're often trying to impress you with their sense of humor. Giving you a hard time is sometimes a way of flirting.

Mirrored body image (mimicking what the other person is doing, like crossed legs, hand on chin, etc) demonstrates interest as well and shows that you're in sync with one another. Using someone's name in conversation is a way to make them feel closer to you.

Most people make eye contact when carrying on conversations.

Therefore, it isn't a good idea to assume that everyone who makes eye contact with you is sending a message of romantic interest.

There is a big difference between a polite smile and one that is truly open.