People get rejected for all sorts of reasons. The important thing is to not take it personally.
1) Sometimes we meet people at the wrong time. It's possible those guys you asked out were in a weird place - in a relationship, dating lots of people, or getting over previous relationships.
2) Just because we perceive ourselves to be a good catch, it doesn't mean every person we like will agree.
3) While it certainly helps to be beautiful and nice, that's not all guys are looking for in a partner. A guy needs to find a girl who he is compatible with. For instance, if he might want to find someone who shares very specific interests with him, someone whose values are similar, etc.
4) Some guys prefer to do the chasing rather than be chased.