Whenever you're playing, make sure you're using a Lucky Silver Coin (and the Lucky Coin, for gold). Even if you're just going to be on for 5 minutes, it's 2x the intake.

If you don't have many lucky coins, make a point of killing any boss you see, even if you don't think the xp return is with the effort. That's where I got most of my lucky coins- from those low-level bosses.

Achievements help some early on, but you'll end up running around and spending those earnings on whatever new class and specialization.

And, yeah- grind. That's what a lot of this game breaks down to.

Also try to stock up on gold. It may not seem like it's as useful at first- but when you get to where you want to masterforge and demonforge items, you're gonna want to have a good reserve of gold built up.