The quality of the oil you use can make a difference in the amount of smoke too.
Cheap, Lubrimatic or WalMart brand oil will smoke more, and doesn't burn as clean as a higher quality like Penzoil, Yamalube, Quicksilver, etc. It costs more mostly because it's better quality.
However, if it's running too rich, it'll smoke no mater what, as it can't burn the excess fuel/oil.