The last few times I played through this game, my characters were incredibly weak throughout much of the start because I have difficulty properly distributing my skill points. On some levels I put them into skills and on others I spend on improving mastery. All too often, I struggle fighting Nessus. So far, the only time I've had it easy was when I choose Nature and build up Call of the Wild enough to get two wolves before putting any more points into the master bar.

How do you spend your skill points each level up? What skills should I focus on developing in masteries early on in the game? How often should I spend points on improving mastery?

Can't really say without knowing what class you want to play, but usually I go just one point in any skill I want to use and the rest are climbing the mastery bars since they help with your survival. Exceptions to that are Warfare's Onslaught which I'll max asap and wolves if I'm playing Nature as I can get 2 out very quickly so they can do all the work.