The first stage of any negotiation is the exchange of information. Both parties convey their views on the problems in a non-confronting manner. The trick here is to decide what to show and what to hide. The information you share with your counterparts will familiarize themselves with a certain fraction of your position. However, it would be like cutting the branch you are sitting on, if you give away too much information.
It is a wise move to have a little chat with the other counterparts in the negotiation, before revealing your cards. This will set a positive vibe. You might find some things in common, such as likes and dislikes between you and the others.
If you jump straight into negotiating, then others might think you to be hasty and aggressive. Some people may actually desire negotiating in this style. However, an informal conversation would come in handy when it comes to negotiations.
Of course, in case of introductions and preliminaries, it is advisable to stick to formality. The best way to introduce yourself is to present yourself in a relaxed and friendly manner with some formal restraint. It would be too foolish of you if you seem to try to bleed your opponent dry. This sort of an approach will make them defensive, which will go against the negotiation.