First time I was going to Maxos Temple, I was L11/12, but I came back and find more enemies in Brocken Valley and solve quests ...
Another thing I will say:
I play with a combination of 3 things:
1) a bow and rangerskill "Stealth" (most enemies I can see with Stealth before they see me

)
2) most of the time I go first (when I have an enemy in focus) for Magic Missile spell + passive Skill "Confusion" (that confused the enemie when I attack it with a spell!) and then on I change between this spell and shoot with my bow ...
3) if some enemies surrounds me to close, I do "Wirlwind" with a good one or two-handed melee weapon and at the meanwhile I repeat Magic Missile so it is necessary!
4) When than enemies are to hard, I run away or jump or roll left or right away from the enemies and make my a new possition in battle...
Sometimes it is funny to go hide me behind a tree, rock or something and Magic Missile can do so good things in that case