To start, find out what interested the young man. This information can help you very seriously when meeting or in the process of communication. However, it is possible to extract only if there is mutual friends you have with him. Generally speaking, common friends in this matter - it is a big trump card. Firstly, they may, in fact, to introduce you. Secondly, can, mentioning you in a conversation with him, do you good publicity in absentia. And thirdly, as has been said, can produce useful information for you.
If friends can not introduce you, take the initiative in their hands. Remember that an important role in future relations plays a first impression. Try it to be good. Carefully consider your appearance, hide all the flaws, emphasize dignity.
Proceed on the situation. If no suitable occasion to discover, invent it. The classic option is to rewrite the abstract request, or to clarify some drawing from a lecture or explain the solution of any problem. The latter option is particularly good because that way you will emphasize that consider the object of your sympathy far more intelligent than his fellow students.
It is also possible, for example, to ask him the results of yesterday's soccer game, if you do know that he's a fan of the sport. However, then you also have to play the role of football fans to talk is not stalled on the first replica. As you know, instead of football can be any other action: a concert rock band, performance, etc.