A higher level of respect than -san. Can be used with a surname or given name, although being used with a surname is more common. Can be used for someone you greatly admire, but professionals of most areas are referred to as -sensei, or simply sensei.
Chotto matte, Saitou-sama. Gomen ne. (One moment, Saitou. Sorry.)
Used with masters of any profession. Teachers, scholars, etc. Can be added to the end of a name (usually the surname), or simply 'sensei' in replacement of any name at all. Not to be confused with someone who is of higher status than you in the school or workplace (-sempai).
Saitou-sensei, kono tegami o Eigo ni yakushite itadakitai desu. (Teacher/master, I would like you to translate this letter into English for me.
Japanese equivalent of Mr/Mrs/Ms. Most often used with a person's surname, less commonly used with a person's given name. This is used for someone you do not know very well, like a classmate who isn't your friend and isn't in a higher grade, or a co-worker who isn't higher status than you.
Saitou-san wa Tookyoo ni imasu. (Mr/Mrs/Ms Saitou is in Tokyo.)