If memory serves, you can simply put a werewolf skill or two on your skill bar during normal gameplay, allowing it to level as you do other things. You can also slot the skills before turning in any quest to put a large amount of experience toward the skills.
Leveling up the Active skills in the Werewolf line can take longer than expected, since you will only earn experience towards these skills while they are slotted in your skill bar, which can only happen while you are in werewolf form. The Werewolf Transformation skill itself will level even when you are not in werewolf form, so long as it is slotted (since it is an Ultimate), but the regular Active skills require you to transform regularly in order to level them.