1) 200% bonuses are key if you're only trying to rank.
2) If you're a melee anything, you can solo extremely easily with a Galadon merc. Aim for 100-200xp mobs who don't hit you as opposed to 300-400 ones who get you to half the health.
3) If you're a mage, get a merc and a golem and aim for 100sh mobs. There is a range where being a mage is an advantage, but it wears off. Ask to be bitch-ranked at every opportunity of anyone in 'who gr'

I was able to rank very non-tanky chars to hero lately without many problems. Sure, sometimes you're stuck on 45 for what seems like forever, but one good session will get you there and it'll come around eventually.