I would suggest giving actual examples of what's right and what's wrong through role play. Like for each thing you're gonna touch on, show the wrong way first, then explain the right way and why its right, then show the right way. Switch it up on them and show a few as the right way initially to see if they're paying attention.

Introduce the PNM to the sister...

Sally PNM, I'd like you to meet my sister Ann -- Ann, this is Sally PNM and she is a business major just like you & Jen.

Also - I thought this was a given, but I'm surprised to see people still doing it - no watches for the sisters. This will discourage them from looking bored and at their watch constantly.

Finally - no rush crushing - there will always be the it girl at the party that everyone wants to bid -- make sure she isn't being over-crowded because a) she'll feel like she's being stalked; and b) other PNM's will notice and wonder why she's getting all the attention.

Everyone probably already knows this... but no perfume for the sisters. There will be enough from the PNMs, and when it blends together it can be...unplesant. Not to mention some people are allergic to it.

We had a chapter rule of no smoking during recruitment. The first day was the worst because there were 13 groups & not smoking after lunch was awful. I remember wistfully watching the other girls (whose house backed up to ours) as they smoked & wishing I could have a cigarette too.

Don't overwhelm a PNM, either. Like the comment about rush crushing--one of the chapters when I went through found out I was a legacy (found out in December after registration and fall parties were over with), and suddenly chapter officers, alums, and all kinds of people started coming up to me along with the girl who I was originally talking to in the room. It was a little uncomfortable, even though I knew it was all in good intent and they really wanted to see me back, but if there's a legacy and she'll probably be back, try to spread out the officer introductions so they're not like, "you're...ummm...Katie! no wait, that was the <i>assistant</i> treasurer...Mary? Jenny? Ummm." if they come back!

ETA: on the subject of unpleasant smells...rooms are crowded, and even if you'll freeze outside, deodorant should be an automatic must. I also wouldn't try anything too new in terms of appearance, either. New shoes may get uncomfortable halfway through the day if they weren't broken in beforehand and new hair and makeup things sometimes don't work. Look clean and polished--no overly loud eyeshadow, exceptionally odd hair colors (depending on the chapter and how uptight folks are about unnatural hair color), or things like that.