The best thing to do is enjoy yourself and trust the right person will notice and ask you out.Flirt a little with the people you're interested in and see what happens.
The look on a person's face is also a good giveaway.
Sometimes, the best way to know if someone is attracted to you is to send a flirting signal and see what happens.
Try being a little friendlier and see if the person reciprocates your energy.
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.