I know for informal recruitment we've done "wear a purple, black, or grey top and dark wash jeans and cute shoes/accessories that match". You could do the same but maybe brown, pink, and white for Gamma Phi.
If you wanted it to be less formal you could say just wear cute tops/blouses, dark wash jeans, and matching accessories. That might be too open ended though, so you could also specify no bootcut/jeans with holes, black or brown flats or heels (no 'going out' heels, etc). Be as specific as you'd want to be/need to be. Also there is a thread
here with pictures to give you ideas.
Threaded Mode
