If a person doesn't like you then it'll show in how they behave towards you. You should watch out for a number of things, some of which include

1. They will be rude to you: This doesn't hold true to every situation or everyone, but most often, if a person doesn't like you then they'll probably be very rude to you.

2. They're body language will change: It's very possible to hide the way you feel about a person with the way you talk to them, but body language isn't so easy to mask. Watch out for signs like sunken shoulders or rolled eyes anytime you step into the room or ask them something.

3. Forced smiles: You'll probably notice that every time you talk with them they'll almost always wear fake smiles because they obviously can't wait to get away from you, but they don't want you to know that.

4. Zero eye contact: Nobody likes making eye contact with people they dislike, and if you haven't been getting any eye contact with the person then there's a good chance they don't like you.

5. They never want to hangout: No matter how many times you ask them to come over or meet you somewhere, they always make an excuse. I'd you have a friend like this then they just might not like you.

6. You feel it in your gut: Intuition is a very powerful thing and trust me when I say that if your body tells you that they don't like you, then chances are that they don't!!!