It depends on the drawer slides. The most common kitchen slides go on the bottom corners. Some go on the bottom center and some can mount anywhere on the sides. Keep in mind that you have to build the drawer to a size that allows for the slide you are using. The common 3/4 extension slides take up 1/2" each side for example.
Someone I consider a master woodworker once told me that a master woodworker is not someone who never makes mistakes. He is someone who is able to cover them up so that no one can tell.