What u need is:
1. physical accuracy so ur white hits dont get dodged. i dont advice to use any dex at all, not invest in accuracy gear/runes. just try to handle enemies of not much lvl difference with u and u wont have dodge-issues
2. train ur mainhand weapon skill so ur hits dont get missed. u can do that by white hitting self-regenerating targets (eggs in ravenfell, eggs in tergothen, devices in sarlo etc; ask ur guild/server, they ll guide u through it)
ps: u can use either staff or wand+talisman as w/m weapon of choice. make ur choice early. 99% in endgame u ll be using wand+tali, so if u r using staff, drop it and start using wands (and lvl them appropriately by afking). u dont want to lvl staff high enough to realise that u need to swap to wand and enjoy 90% misses cause u ll have it un-lvled
Cheers