#1: Anyone afflicted with lycanthropy will become a werewolf.
Such persons are known as lycanthropes. If that word is too polysyllabic for you then I suppose you can employ the term "lycan" (sigh). Lycanthropy slowly makes one become evil. Period. There is no such thing as good and heroic werewolf in my world. If you desire to consume that kind of post-Buffy supernatural reality I strongly suggest you try other websites.
Next, I must emphasize that the vast majority of people afflicted with lycanthropy cannot handle it, especially once they realize the full gravity of what they are becoming. Only the minority survive the first year or two, and accept not only their new reality, but all the consequences that accompany it. These folks very often grow into powerful beasts, of whom I sometimes refer to as veteran werewolves.
#2: A person with lycanthropy is weakest during the new moon, and strongest at the full moon.
This rule works in degrees. For example, after the full moon as the lunar cycle progresses to the new moon phase, the lycanthrope's overall energy slowly lessens. His/her energy declines, as does their stamina and virility. Of course, as the days tumble towards the full moon, they become more energized, hungry, and attractive.
#3: Even the most veteran and able of lycanthropes cannot voluntarily transform into a werewolf on the new moon.
Conversely, during the night of the full moon even the most veteran and able of lycanthropes cannot resist transforming into a werewolf. This rule, when viewed with Rule #2 in mind, suggests that it is harder to voluntarily change into a werewolf as the new moon approaches, and easier as the full moon approaches.
Stay tuned for more... oh wait, before I go I must credit fellow werewolf enthusiast James for helping me shape these rules and the ones I will post in future blogs.