I know some have already been covered, but here's my two cents...
*DON'T dress provocatively. You're going through sorority recruitment, not clubbing.
*DON'T wear perfume. At least at my school, you're packed in fairly small rooms with lots of other people. If everyone is wearing perfume, it can get a bit overwhelming.
*DON'T discuss how much you want to hang out with fraternity guys, get drunk, etc. It makes the rusher wonder what your motivation in joining a sorority really is.
*DON'T talk about having a rec.
*DO show interest. Real interest, not faked.
Boredom shows.
*DO BE YOURSELF!!!
*DO have fun!!
Hybrid Mode
