Do some quests that don't involve fighting if you've got any.

It is a good source of xp outside fighting, and even one or two levels make a great difference in the beginning.

Also: recruit a companion if you find one.

Ah yes, but getting in there's a bit of a pain. I find it easiest to get in with a significantly diplomatic build, myself.

Yep. The game's huge. I think I'd been playing the game for ten years, and not seldom at that, before I found out about the Deathclaw cave near the Hub.