Humiliation is one of the hardest to define subjects in BDSM because there are no physical signs and effects but humiliation is all in a persons mind. Humiliation can be used as part of dehumanization.
Humiliation can be archived in many different ways, however it is important to remember that no two people will experience humiliation the same way. I’ve met girls that were proud of the large number of men they’ve slept with and were therefore proud to be called a slut. Other women will find being called a slut very humiliating.
Verbal humiliation includes everything from name calling to lecturing. The words used for verbal humiliation can be insulting (bitch, slut, ...), belittling (girl, pet, ...) or used to refer to shortcomings of the subject (calling someone fat, stupid and so on).
From a goldenshower to forced crossdressing, physical humiliation comes in many forms. This form of humiliation also lends itself very well to public humiliation since many forms of it are - while socially not accepted - not illegal (i.e. crossdressing).
Behavioral humiliation refers to any form of humiliation where the subject is made to behave in a certain way. This can mean acting like a person of a lower status (an adult baby or a school girl) or being treated as an animal (see dehumanization, pony play or puppy play).