The points below have been written keeping the level of relationship in mind. Each point is a progress in level.
Notice where he is staring
Does he stare at you when you are away talking with your friends or doing something else for that matter? Guys tend to secretly stare at girls they admire and like. They try to watch what the girl does and the way she behaves. So if you find a man constantly staring whenever you pass by then chances are that the man likes you and is attracted towards you.
The man's smile
How a man smiles at you can pretty much reveal his thoughts. Is it an informal smile or is it deeper. Does the smile last for a considerably longer time or does it get cut off just like a formal hello. Also watch the man's eyebrow. There is a raise and fall in the eyebrow when a man looks at a woman he likes.
Mirroring is a phenomenon in which one person automatically mirrors what the other person is doing. Like for instance, when one person leans forward to tell something the other person leans forward too to meet the other person's lean. If one person sits back the other one sits back too. This generally happens between two people who are attracted to each other.
Mirroring is a part of body language of a man that happens almost subconsciously when he likes you. So next time try to notice and see if your man is mirroring you.
When your guy is talking to you notice how many times he blinks. An increase in the blink rate directly indicates attraction.
Change in looks
When men are in love they try to take better care of their looks. Although this can also mean that the man could be in love with anyone. So you can take this tip in accordance with the above points
Is he trying to help you out where ever possible? If a man likes you he will try to help you out and make your life that much more easier.
Curious to know more about you
Does he ask you all kinds of questions about your interests, likes and dislikes? This is a solid sign that the man likes you and wants to know more about you so he can take the relationship to the next level
Finding out if you have a boyfriend?
If a man is really serious about you, then he will definitely try to find out if you already have an on-going relationship with another guy. Some men might ask you this question directly whereas others will try to find this out by some other means like asking your friends or someone who is close to you. He might even ask you indirect questions like what you generally do on weekends and stuff. All these are ways to find out if you already have a boyfriend. Once a man is sure that you are single, he will make his next move or wait for you to make a move by giving you all the right signals.
Letting you know that he doesn't have a girlfriend
Once a guy is sure that you are the right girl, he will also try to pass on the message that he is single too and is open to dating. He will try to tell you directly or indirectly that he does not have a girlfriend currently.
"If a man is serious about you, he will definitely try to find out if you already have a relationship."
Asking for a date
Fear of getting rejected stops most men from making this final move; which is asking a girl for a date. Most men will instead send over signals that they want to date you. Some examples are asking to drop you home (if you are working in the same office or studying in the same school/college), spending money on you by getting you goodies like CDs, books etc. treating you will respect, telling you about his weekend plans which involves going to the movies alone. He will try to see if you pick up the opportunity and ask for a date.
Taking the relationship forward
Once you start dating, you can easily find out if the man is really serious about you. If he is serious, he will maintain daily contact with you. He will start introducing you to his friends, his family and relatives. A man will also start opening up a lot more at this point, letting you know his true feelings for you.