The handshake close
Handshake contracts are a form of verbal contract and can be Legally binding. Handshakes only can be a tough thing to prove in court so I would back it up with some kind of letter of agreement. It very much comes from the old days where your handshake was your bond of honor.
In terms of a negotiation tactic, when you come to agreement offer your hand and shake on it as a non-verbal agreement. There has to be three elements.
An offer of exchange
Some form of acceptance
An area of consideration for example a price
There are also some hints for basic business etiquette.
Saying hello or goodbye in business meetings
Don’t be too limp, clammy or crushing in your shake
Look them in the eye when you shake hands
Stand up when you do it
Don’t have other hand in pocket
Keep your hand straight up and down
Understand personal distance, people from the country will leave a wider gap
In the old days the man would wait till a woman offered her hand. It’s outdated, treat everyone equally.