One of the key areas to level is do you sector patrols. The original mission assigments to explore the various systems have been basicly removed from the mission lists.
While doing the episode missions in the various quadrants like Psi Valorum, Iota Pavonios etc., the various systems that are there will have little gear wheels if you mouse over them.
Those will have patrol missions within them and they will give insane amounts of XP which in turn will level you quickly.
I tested that theory of leveling in that fashion and from Ensign to Level 50, I finished a character in under two weeks. There are some of our members who do that insane leveling in 3 days...
The down side of the insane speed leveling... Your character will be doing missions that were orginally done by players when their characters were at around LT. CDR to just CDR.
Pace yourself and prep for the next rank. Start looking for the next tier gear when you make your new rank. Be sure to get your crafting leveled as you go so you can craft gear that might not be available in the Fleet Banks or even on the Exchange.