Honorific titles

-san (さん), the most common, implies that you have had some acquaintence with the person; less groveling than sama.
-shi (), similar to san and sama as used in formal writing and very, polite speech, for referring to a person completely unfamiliar to speaker. Preferred in legal documents, journals to avoid familiarity of san and sama.
-sama (), formal version of san used in addressing persons of higher rank, also customers. Ore-sama, "my esteemed self," may be used in humor.
sensei (先生), refers to teachers, doctors or other authority figures.
senpai and kohai, senpai (先輩) is used by students or subordinates of their seniors; kohai (後輩) is the student or junior.
-kun (), used informally for boys, masculine of chan.
-chan (ちゃん), used informally for girls, feminine of -kun. Diminutive, "loveable" and for pets or animals.