Necro has the highest potential on AoE for Outlaw, but it’s also a bit harder to play and not what I’d recommend for someone starting out.
Venthyr Outlaw is also perfectly viable, you just swap to the Blunderbuss legendary. Much easier playstyle and still pumps.
If you’re going to be playing with pug groups, I personally think Outlaw is a bit better. Sub is great if you know your tank is going to be doing a lot of huge pulls, but pug tanks are unpredictable which can be frustrating.
Outside the damage/rotation stuff, practice using your utility as well. Focus on interrupting casts (remember your Gouge as Outlaw ) and stunning dangerous mobs. Be aware of your surroundings; you can use Distract to stop a patrol at an optimal point in their path (or prevent them from getting close enough to aggro on your party member who isn’t paying attention).
Hard to give more specific advice without knowing what spec you’re playing.