The best thing I've found that works for me with targeting (and this is highly dependant on what role you're playing) is to set up the filter for whenever my weapon is drawn. Since I'm dps, I have it set to enemies only and it's worked wonders. I couldn't get the filter to stay on enemies, it would always switch back to other (I think). I'm sure there's a way around this.
And reposting since I didn't get any answers this morning:
So, I hit 46 today and my next story quest is at 49. I've done every single side quest I can find throughout the zones they've sent me to. Am I really going to have to dungeon, leve and guildheist all the way to 50 or am I missing some zones? Xp has literally slowed to a crawl at this point.
Well there's the challenge log, the hunting logs, XP for exploring the entirety of maps. (Exploring the overworld everywhere will aware you most of a levels worth of XP.)
You probably are going to need to re-run a dungeon or two though, though it is very likely that you overlooked a side quest or two.