Choosing to be a dark elf will mean that the overall weakness to fire for the vampire hero is only -50% (inherent fire resistance of dark elf) rather than -100% at highest level.

Reserve the perk points from the sneak ability and redistribute these in other abilities to maximize the vampire hero's all round abilities.

Maximize the Backstab option, as the vampire hero can sneak better than most and deal a lot of damage to enemies from behind whilst sneaking.

Press J and use journal to check on the time of the day. When within buildings and underground, it does not really matter what time of the day it is for the vampire hero.

Use fast travel during the day, and reserve the night for travel in the wilderness.

Here are some hints and tips on maximizing the vampire powers of the hero. In Skyrim, the vampire hero must maintain his vampire powers and balance these with his other skills such as destructive magic or sneak attack to fully maximize his potential in all his abilities. Skyrim Vampire Powers - Press P and scroll to check on vampire powers (vampire servant seen here) Skyrim Maximizing and Maintaining Vampire Powers

Skyrim where to find vampires