I've been to some Lia Sophia parties, and before I made soap I hosted a Body Shop party, so I can advise you based on those experiences:
The host gets gift(s) as incentives. With the Lia Sophia parties, they get a choice of various jewelry and/or discounts on jewelry. With Body Shop, I got a choice of free stuff plus discounts on other stuff. It's based on how much is sold at the party, so there's a basic hostess gift for just having the party and additional gifts/discounts for more sales at the party.
The hostess also gets additional incentives if guests at the party sign up to host their own parties. It's a good way to perpetuate the cycle.
The hostess invites the friends and provides all refreshments.
If you have small stuff, you can do a door prize as a freebie to a guest, or after you talk about your stuff, ask the guests a question about some detail you relayed, and the first person to remember and answer correctly gets a prize.
For jewelry, a nice display and lots of mirrors are key, so make sure you'll have space to set up and bring a table cover for a nice blank non-distracting background, and if there's nothing suitable, bring your own table(s). A dining room table is good, though.
That's all I can think of right now.