most people wont be straight up with you. they will start giving you short answers not returning phone calls, etc.
======
You will know as they will definitely be interested and seem nervous around you.
If you already know someone is not interested in you it is best to let them be as they won't change their minds.
It is hard to tell. Just tell that special someone about your feelings and they will let you know.
By getting to know him first. You should never jump straight into bed with someone you don't know. If this is what he want's you to do then obviously he is not interested in you as a friend, but a sex object.
It would depend on how old this other person is and if you are interested in them. If you like them as well talk to them and get to know them, if you are not interested you don't have to do anything except tell them you are not interested if you are approached.
that they are interested in you and want to persue getting to know more about you
If she flirts with you and seems generally interested in what you have to say, then yes, she probably likes you.
Ask every customer and prospect you meet. Even if they are not interested they may know someone who is.
see what they are interested in talk about there life and just get to know them
I don't know but would be interested if someone foes
you don't. you get to know her first, then make sure she is really someone you are interested in, then ask her out if she is. good luck with that =)