What contrasts are brought out between the characters of Hamlet and Laertes In Act1 Scene 2?
Concerning contrasts between Hamlet and Laertes in Act 1.2 of Shakespeare's Hamlet, the real answer is that there is no comparison or contrast. By this point in the play there is no "basis of comparison," no reason to compare or contrast them. Laertes barely appears in the scene. Later he will serve the purpose of providing a foil for Hamlet, but he certainly isn't of much importance at this point in the play.
In contrast, Hamlet is revealed to be highly intelligent, witty, in possession of an incredibly creative mind. He is able to think for himself, and does not accept authority that has not earned his respect. Look at the "seems" speech. Hamlet is the giant of this play. Laertes is nothing at this point.
In addition to his intellectual powers, we learn in this scene that Hamlet is suffering from depression. He is intensely loyal to his father as well as extremely fond of him. Hamlet can feel, as well as think.
To me, the major contrast that is being brought out in this scene has to do with how decisive and determined Laertes is and how Hamlet has the opposite qualities. We will also see Hamlet compared in this way to Fortinbras.
In the scene, Laertes is going to be going to France. He has determined that he wants to go there and he has (Polonius says) worn his father down by aruging that he should go there. So Laertes knows what he wants and pursues it.
By contrast, Hamlet does not want to be around his mother and Claudius. But he is not decisive like Laertes. He lets Claudius persuade him not to go back to school even though he hates being there at the castle in these circumstances.