Lonely Planet outlines some important customs to keep in mind
Stepping over people’s legs in Nepal is a social taboo, and anywhere in Asia touching any part of another person’s body with your foot is offensive because feet are the “lowest” part of the body. Apologise immediately. Don’t touch people’s heads in Asia either as one’s head is the “highest” part of the body spiritually. The people of Fiji can shake hands for several minutes. In Italy, men can be seen walking together arm-in-arm, as can women. In Russia and parts of the former Soviet Union, don’t shake hands, kiss or hand something to someone across a doorway as it’s considered unlucky.