You should find out what he is interested in and talk about that. Don't laugh unless he makes a joke or is trying to be funny.
either they are secretly in love with you, or, someone is just trying just to be friendly.
Mostly, if there are "trying" to make you laugh, and trying to act funny in front of you, and not being themselves, mostly.............. they like you!! Good luck :-))
You can look really good, and laugh at the object of your affection's jokes.
laugh at all of his jokes and do physical contact when you talk to him
You can laugh sweetly and give him a smile. It depends on whether he is doing it in a friendly way or a flirty way.
Just Make em laugh or be friendly to them
In fact, he's wanting to laugh, and is using you to make him laugh too.
You start with a smile and a friendly conversation. Then you make her laugh. Women and girls like someone who can make them laugh.
You need to see how she acts around other people as well as you. If she's only flirty or is extra flirty around you, then she may like you. If she is like that around everyone, then she's just a friendly person. Be nice and make her laugh. If she's flirting with you at all that must mean there's something about you that she likes or is at least worth being around.
by trying to change the subject,or when they laugh you laugh too.
I just think she was just a friendly laughable person - I don't think she had a reason to laugh so much
because you are a very serious person or your friends are trying to impress you :D