You do indeed need to COB like whoa.
My advice would be to look for women who want to be in KKG specifically - not who just want to be in a sorority. Avoid flyers and chalking - they attract the latter and make it very hard for you to be selective. That is, if the whole campus knows you're looking for members, the loons will come out demanding bids and it's very hard to say "we don't want to bid you because you're a loon." They have you over a barrel, as it were. COB parties should be invite only. Each sister should come up with at least one person to invite. Also, you don't have to expressly do "parties" - try inviting women to dinner if you have a house with a kitchen, or to events you're attending as a sisterhood, like campus speakers or theater productions.
Above all, don't get scared and bid people just to increase your numbers if you're not really crazy about them. It will bite you in the butt eventually.
