Few things you can use to do better:
- Potions. Get both physical and magic potions before the fight.
- Decent blood. Scholar is good for ranged, brute/warrior for melee.
- Try different spells, especially if you have trouble dodging. Shield/counter spells especially. You can have 2 shields just fine.
- Finally you can wait till there is a bloodmoon, which boosts you blood type bonuses. But this is hard to time.
There is a way to “bypass” bosses by adjusting the server settings to set the difficulty to trivial levels, although that would spoil the sense of accomplishment.
You could always do that and then gradually increase the difficulty back to more default levels as you get used to the game and your skill improves.