Extending eye contact for brief moments longer than expected can add intimacy to a casual encounter and can definitely be one of the signs of flirting.
If you notice someone on the other side of the room trying to catch your attention, and then smiling when you make eye contact, that can be a sign of flirting.
To test it out, smile when the flirting suspect catches your eye, and then glance away for a few seconds.
When you look back in the person's direction, if he or she is still looking at you, it's a pretty safe bet that flirting is taking place.
Seemingly casual touches during conversation can sometimes indicate romantic interest.
Depending on how it's done, and the personalities of the people involved, simple touches that seem to be very casual can be flirtatious.
If you move away when someone casually touches you, you'll be sending a sign that the flirting behavior is unwelcome.
Some flirting signals are obvious, like touching, and other flirting signs, like eye contact or compliments, are more subtle.
Actions that you think might just be friendly gestures can actually indicate romantic interest.
Therefore, it isn't a good idea to assume that everyone who makes eye contact with you is sending a message of romantic interest.
When a person holds eye contact for just a few seconds longer than what seems natural for a particular conversation, however, there's a good chance that he or she is flirting with you.