Leveling advice, 50's in LA invasion?
Staff and wells is definitely the way to go. You will not be able to handle 1v1 with potential for more spawns while you fight.
Trait for staff mastery, greater marks, focused rituals, and ritual mastery. Stay out of range if you do not have support from others. Tag everything for loot but watch your six as new spawns pop frequently.
Well of power and the NPC speed boost are your friends. You should think about locust signet, too. Do not run war horn as it tags mobs in AoE and will draw you down to combat speed. If you need another speed boost, there is spectral walk but it has a long CD and is not a good escape while locust is much more dependable for a 5/6 of a full swiftness boon.
Not to mention with the sheer number of enemies that spawn there, activating Locust Signet provides a nice heal in a pinch.
I used wells and Life Transfer to tag as much as possible. Lvld my necro from 40 to 80 in a few days. Warhorn is great too.