When you have alcohol, it must be drunk until it is gone.
One should not put a glass with alcohol back on the table.
Traditionally alcohol is poured out to all the people present, though they are not required to drink.
One should not make a long interruption between first and second shots.
The latecomer must drink a full bottle. (so-called "penal")
Outgoing guest must drink last glass, so-called "na pososhok" (russ. "На посошок"). Literally it is translated "On a small staff", really means "For lucky way".
As a rule, every portion of spirit is accompanied by a touch of glasses and a toast. Funeral and commemoration are exceptions; there the touch of glasses is forbidden.
It is not allowed to pour out by hand holding a bottle from below.
It is not allowed to fill a glass being held in the air.
It is considered bad luck to make a toast with an empty glass. If done, the toaster must finish off the bottle of what he had last.
It is considered bad luck to put an empty bottle back on the table when it's finished
See full set of Russian traditions and superstitions at http://en.wikipedia.org/wiki/Russian_traditions_and_superstitions