You could join or start a Free Company that's oriented towards welcoming and helping new players.

You can also just be regularly helpful in whatever content you're doing, especially if you see you're partied up with a Sprout or Returning Player. Ask if anyone needs help and, if you see a player struggling with content or mechanics, ask if they would like a hand (but try to not offer unsolicited or targeted "advice" even if it's meant well). This will not only let you be a friendly helpful force in the game but will also help you get those commendations you need a little faster.