You also want to find out a little about your would-be mate's history and current interests.
Without knowing what to ask or say, you could spend weeks or months with someone that isn't right for you.
When there is an attraction, both people will feed off that attraction and want more.
Just make sure you're not projecting your attraction on to another person.
There may be hints of attraction if you catch someone gazing at you.
In this case, "Attracted is attractive" because people tend to like the people who find them interesting.
You can often see the spark in eye contact or a smile.
However, if a person is too shy, eye contact might be avoided, but once that person does catch your eye, you might notice it's an invitation to come over and talk.
The attraction deepens once the eye contact is returned and held.
According to another Scientific American article, dilated pupils are another sign of attraction.