Before you figure out how to become a werewolf you should first make sure you know what you are getting yourself into. Modern popular fiction has confused the issue quite a bit by altering the definition of what a werewolf really is. If you haven't already, it would be wise to read the descriptions of the different creatures we call werewolves on the main Werewolf page.
I'll give a quick recap. What many people today think of as a "werewolf" is actually a "shapeshifter". Some shapeshifters turn exclusively into wolves from human form, but these are not actual werewolves. These shapeshifter-wolves have become popularly known as "werewolves" because of the Twilight book series. If it's this kind of creature you want to become, I'm afraid you are probably out of luck. Most shapeshifters (wolves included) are born that way genetically. You either have it or you don't, and most of us don't. A bite from a shapeshifter won't make you a shapeshifter, it will just be a bite.
There is a single exception, though. Navajo mythology discusses a being known as a "Skinwalker", who in most cases is a human who has learned how to magically transform themself into an animal by wearing the animal's skin. Skinwalkers are typically considered to be evil, and becoming one takes a great deal of sacrifice and a deep knowledge of ancient mystical arts.
Real werewolfism is a curse. Those afflicted have little to no control over their actions when in wolf form and little to no control over their transformations. Of course, there is an exception to this rule as well in rare cases of Human Werewolf Syndrome, wherein werewolves in wolf form maintain their human consciousness. This rare condition is believed, though, to only occur in cases where a werewolf child is born to werewolf parents.
If you still want to know how to become a werewolf, you can read about how to do so here, but I would advise thinking long and hard about the decision before doing so.