Help them figure out tactics to use. Set up a mock negotiation. Set a target Make it above your reservation point. It's ok for it to waiver during negotiations. Reservation price will waver less but may also change due to new information.
Opening moves Too conservative offers lose value.
Too aggressive offers hurt the negotiating atmosphere and may require big concessions. If adversary is not prepared and you are, then make an offer. It may 'anchor' the negotiations and effect their reservation price. If they offer first then be aware of the anchor effect. Don't fixate on talking about it.