There is a trick to basically every boss.
Whitefang for example, like most other wolves, doesn't like terrible smells such as caused by the "Nasty Oil Coating", and applying that for the day before the battle should make that fight a cakewalk.
For most humanoid enemies their weakness is Lightning damage. There are other ways of beating them too, but if you ever run a NG+, start with Thunderbolt already learned and use it on them on the correct turn, before they use their big damage skill such as Rampage, and they won't be able to use it.