This really depends on whether you like the guy or not. If you do like him then the fact he is staring should be taken as a great sign he is interested.
Like the movies do so well, this is your cue to make him want you even more. Don't let on that you know he's staring but get your best visual flirting game on. This can be running your fingers through your hair or maybe seductively licking a lolly or taking a drink. Just treat it as a bit of fun and relax. Then near the end of your little show you could make eye contact with him and smile. He is sure to love this and this eye contact and smile might give him the 'green light' to come over and talk to you or even ask you out.
However if you do not like the guy who is staring, then you need for him to know this so he won't continue. The easiest way of doing this would be to stare back with a scowl. This is sure to give him the message you are not impressed with him staring and that you don't particularly like him. Although this may seem a little cruel and blunt, if you are not interested then it is better for him to know straight away; than get his hopes up and make him feel worse further down the line.
Like the movies do so well, this is your cue to make him want you even more. Don't let on that you know he's staring but get your best visual flirting game on. This can be running your fingers through your hair or maybe seductively licking a lolly or taking a drink. Just treat it as a bit of fun and relax. Then near the end of your little show you could make eye contact with him and smile. He is sure to love this and this eye contact and smile might give him the 'green light' to come over and talk to you or even ask you out.
However if you do not like the guy who is staring, then you need for him to know this so he won't continue. The easiest way of doing this would be to stare back with a scowl. This is sure to give him the message you are not impressed with him staring and that you don't particularly like him. Although this may seem a little cruel and blunt, if you are not interested then it is better for him to know straight away; than get his hopes up and make him feel worse further down the line.