Everyone loves a good western movie ! And I'll show you the conventions that you are expected to find in a good old time movie like this one, "Il buono, il brutto, il cattivo" one of the most amazing western movies that have ever existed!
Western movies use to have the same layout, a good and a bad guy, usually the good guy has lighter clothes, using white and camel, on the contrary the bad guy is always presented using black clothes with a scary face that makes him emerge from the rest.
Usually the time used portrays how hard it used to be living in the American frontiers, always having to fight the bad guys in order to get their village in peace.
Some conventions that you should expect in a western are the revolvers, cowboys, saloon doors, desert , horses, cows and so on.