Great (Chaos) Fireballs are always a good option to one-hit the Dog Skeletons. The big skeletons are easily staggered with a heavy weapon, that might help. The thing is, both of these enemies aren't too hard to fight, weren't it for the creepy low visibility/high amount of cliffs environment they're in. There is literally little room for error.
Recently I made a level 99 Quality/Faith build to do some buffed PvP-ing in the arena. Turned out he sucked. Now I'm gonna level up my intelligence, turn him into Artorias and go NG+infinity till whenever I can't handle it anymore. Pow! As I've never gone past NG+, nor used Artorias' Greatswords, this should be a nice challenge. I also sort of miss co-op in this game now that I'v been doing solo-challenges and PvP-ing so much. Let us return as a sunbro!
Edit: Went NG+ and got invaded by a semi-low level on the bridge with the Hellkite dragon and lost to 3 lagstabs. Sometimes I really can't stand losing >: ( I will dedicate this character to the Sun and sending home invaders! PRAISE THE SUN.