While most people only have two hands, they shake many, many more throughout their lifetimes. But apparently, as many as 20 percent of people don't entirely know the right way to do so, which is why scientists from the University of Manchester have outlined what can be called best practices when it comes to shaking hands, according to a video on Slate:  

• Use the right hand, full grip with fingers under the palm (not the fingertips!) 
• The hand should be midway between the both of you.
• Shake with a firm squeeze: not too hard, not too soft. 
• The optimal number of shakes: three, with medium vigor. 
• A hand shake should not last more than 2-3 seconds. 
• Maintain eye contact throughout. 
• Pair handshake with an appropriate verbal statement ("nice to meet you," versus "did you just come from a seafood restaurant, because that hand sure is clammy!")

And there you have it!