How do you levitate?

Levitation is not possible. It is an illusion.
Levitation is believed widely to be impossible, however there are some eastern medicinal practitioners and magicians who claim to have achieved this state. Among them are David Copperfield and several others who claim that supreme concentration allows them to levitate.
i have performed levitation in a physics lab on a very small scale...as in I've levitated a small magnet by using the properties of superconductors, with my superconductor being a small piece of procelain. as far as human levitation, which i am assuming is what you're asking, i believe that most of that is done via illusions with mirrors and glass that can bend light to look a certain way. as a physicist, i have never actually levitated a person, though if you're interested in exploring it some more, check out topics related to magnetic field polarity and see if you can come up with a creative solution!