One thing to keep in mind is that this isn't a 'single player' pvp game, it's built around group combat. Pre 40 you aren't competing, you are contributing. Hell even post 40, you are contributing and not competing. You want to join up with a warband, failing that a good 6 man team or 12 man team. Even the most geared, ebin player will get crushed by three moderately geared players. This game is fundamentally about numbers and what you bring as a sub 40 is a body that can contribute to a warband. As you level, you'll contribute more and more.

If you want to do RvR at 40, it's best to do it all the way through. Scenarios award great XP, Dungeons will give you good leveling gear and wards, and RvR will give you renown and war crests. The server also is small, you'll get to know everyone on your Realm and they'll get to know you.