I have rarely done FPs or heroics, never PvP as I've levelled and I'm usually one or two levels above the starting level for a planet when I hit it.
So, some tips from me. Log out in a rest area. Do at least one daily space mission that is not greyed out. Check for new space missions opening up, they give great XP the first time. Complete any mini bonus quests, especially multi-stage ones. Do the planetary bonus series. They don't always start on the planet and not always at level, so keep an eye out.
That is all I do outside of the regular planetary and story quests and it works out fine for me.