On Bella's first day at Forks High, the first guy she meets is Eric, who eagerly helps her around the school. Bella makes the early call that Eric is a little too clingy for her liking. She seems to favor Mike a bit more, which Eric seems to resent.
Mike is friendly and we assume he's fairly good looking for a mortal. He's the most persistent human vying for Bella's affection, and to his credit, he remains friendly to Bella even after she has rejected him. Mike seems to be the leader of the Forks High School guys. He organizes the beach trip, and he has the best shot with Bella. However, he doesn't seem to clue in to Bella's "I'm not interested" signals.
Then there's Tyler, the one who almost hits Bella with his van (and probably would have killed her, had it not been for Edward's super-strength and super-speed). He assumes that he and Bella are going to prom because he sort of hinted at it once. Like Eric, Tyler is too eager for Bella's liking; and like Mike, he can't seem to read Bella's hints that she's not interested.
In a way, we feel bad for the regular Forks High School boys. How can they compete with a gorgeous vampire like Edward? None of these human guys stand a chance with Bella once Edward steps on to the scene. In fact, the primary role of these ordinary guys is to serve as a contrast to Edward, highlighting how mysterious, interesting, mature, and attractive he is.