What a lot of people don't realize as they're advancing through the levels is that some planets offer a bonus series of missions. At Alderaan for instance, there are a level 40 series of missions that provide some sweet epic loot upon completion. Hoth has a series of missions that are unlocked at around level 47 and Belsavis has a level 50 bonus series mission line that gives you daily commendations. Although some of these missions to go back to the planet are based on your fleet space station, the Hoth one for instance, is only found by travelling back back to the planet once you've reached level 46/7. If someone hadn't told me about the Alderaan and Hoth bonus missions, I would have never known they were there!
What these bonus missions did was to put me ahead of the base level required on the advanced planets. for
example, although Corellia is a level 47-50 planet, I was actually level 49 by the time I got there. I am now level 50 and still have a tonne of missions to complete, which all provide commendations and much needed credits. As all these missions are green to me, they are very easy to complete. I under a week, I've got my 110 speed speeder and I'm well on my way to decking out all my companions. I've also got all my crafting skills maxed and able to craft a number of epic items. My experience on Beta was very different; I had no credits at level 50 and my gear was no where near as good as it is this time and things were a lot harder.
I strongly advise that you take the time to do the Alderaan bonus missions at level 40 and Hoth at level 47.