14 years ago
Looks can be deceiving. Tell him as soon as you are aware that you're not interested. You don't want to delay the inevitable, or give him the wrong impression. If he is drunk, let him know you dig sober people, and are willing to talk when he cleans up a bit.
You can always take the low road and do someting disgusting: Like coughing with your mouth open or clean your teeth (or ears) in public. Or just pretend like you have a weird tick with your neck or shoulder or something. Just don't laugh when you do it; you must make him think that you are a weirdo. (But don't do it when there are other people around you want to impress! Just turn him off and he won't even want to stalk you later.
Make sure you can leave the place as well. There is just no escaping him if he really wants to.
Tell him quickly, and tell him the truth. It doesn't have to be a long conversation. Say something like "Look, I'm really flattered that you like me, and I feel uncomfortable saying this, but the feeling isn't mutual."
Give him some time to have his feelings about it, but don't get into talking about "Why" you're not interested. Anything you say can lead to hurt feelings, and isn't likely to go over well.
Exit stage left. Don't overstay. As soon as he's had time to express his sadness or anger, simply say that it's time for you to go, and wish him the best.
Make it a clean break. It's really important not to lead him on and say things that might lead him to think that there's a chance some day.
Always speak well of him to others. Gossiping, or bad mouthing another person never leads to anything positive. Do not pretend you want to 'be friends'. It's very painful for him if he does not have a lot of self esteem. He'd probably continue hoping you'd turn around.
Alternatively, be indirect. This method works if you don't want to hurt his feelings and you don't know how to explain it to him. However, it's slower and might be less effective.
Talk loudly about things you know he doesn't like around him. For example, if he hates MTV, make sure he hears you talking about how awesome it is. If he likes My Chemical Romance, make sure he hears you talking about how much they suck and how you love Ashlee Simpson. Eventually, he'll realize you have nothing in common.
Rave about how much you love someone else in front of him. Not to him. It might be a little harsh, but it's nicely saying that you're interested in someone else. He might give up.
Begin slowly avoid the places you know he hangs out. If he hangs around the local coffee shop on weekends, go somewhere else then. However, for example, if you regularly hang out there on weekends too, don't stop going there instantly. Just make a few excuses for why you can't go there that weekend and only go there once in awhile. When you're gone, he might notice someone else.
Make sure you're not doing anything at all to flirt when he talks to you. Continue to talk to him, if you already do. Just make sure you're not sending any flirting vibes. Try not to look him directly in the eye, don't touch his knee or anything when he makes a joke, and don't giggle at everything he says. If you talk to him exactly the same way you do your little brother, he might give up.
If all else fails, give it up and use the direct method. It's not worth it continuing to be subtle if he just doesn't get it.
14 years ago
calmly approach him and ask him why hes staring..if he takes it as an insult apologize for thinking wrongly but ask him politely to stop. if he persists, approach him again and tell him its really bothering you. he probably wants you back, theres really no other reason to stare at an ex. set things straight..good luck!