I’m not all about the race to end game (my highest character is currently level 8), but being a little higher than the quest area you’re in comes in handy for easier kills. I’ve been completing every quest I can find, and spending loads of time roaming around pointing my grenades at anything that moves. That being said, for the bounty hunter and imperial agents that start on Hutta, there is an easy way to gain two ‘free’ levels.
First you have to wander your way to the Jiguuna Spaceport. This is just to the right hand side of Nem’ro’s Palace. Take the first right, and follow the hallway down to the end. You’ll find yourself in an open space with some ships you can use for transport. Fly to the Imperial Fleet. Once you’re there you’ll see a quest just ahead of you that offers to teach you about crafting and about social points (which I still haven’t gotten into yet). The crafting quest requires you to speak to crafting trainers and you earn experience for every one you talk to. There are approximately 12 NPC to speak to in total. You don’t have to actually train with any of them, you just need to speak to them and rack up the experience points. Once you’re done and you have your levels you can fly back to Hutta and continue on your quests.