basic Ranger builds?

My little brother is playing this class, and has a very hard time soloing. I'm trying to give him what advice I can, but never having played the class and still being somewhat new, I'm just not sure what he's doing wrong. He has I guess a decent amount of HP and resistance for his level. I think his damage is a bit low, but I'm working on getting him a better bow.

What are some of the keystone and notable passives that Rangers "must" have? I'm thinking it's more of a build issue.

Also what are some of the cookie-cutter skill builds? I heard lightning arrow + chain is a big one?

Thanks for any help guys.