Technically, Darcy proposed to Elizabeth twice. The first one she refused, the second one she accepted. Darcy initially appeared to be a good candidate for pursuing (by Mrs. Bennet's estimation at least) as he was handsome and had a lot of money. But Mrs. Bennet (and the Benet sisters) become soured on him when he is indifferent to the town's show of hospitality, seems overly proud, and refuses to dance with Lizzy (a big no-no of the time).
He becomes more unpopular with Lizzy when he admits to her that he kept Bingley from marrying her sister, Jane due to Jane's supposed poor family relations. Jane was in love with Bingley and devastated when he stopped courting her, which of course made Lizzy upset. To put the final nail in the coffin of the first proposal, he proposes in such an insulting manner that Lizzy is very cruel in her denial of his offer of marriage.