For me it's 3 things that are important, if one is missing there can't be a crush: 1) personality (His character , the way he behaves..) 2) Mentality (The way he thinks, his stance in important matters , if we have compatible values...) 3) Physical apperence
Looks definitely play a role especially at first. Next he has to be humorous which usually means he's intelligent. I also tend to be really attracted to guys who are very motivated. A guy who is kind will always melt my ❤.