Some people comment that reaching a 3.0 will get you a larger amount of gold. It is true... To an extent. To fully reach the potential gold limit, I've found that once you reach around a higher CL than 6.0, and returning to areas such as Zen Gardens, Bassken Lake, and The Old Aqueduct will give you more orbs and gold than training in your specified CL area.
Also, buying a ring off the market isn't such a bad idea. I was a low ranking 3.5 before a friend bought me a 10.0 ring, and it raised my CL, sure, but it also improved my agility and speed as well. Do not make the mistake of looking over non-popular rings such as Bump, Scaredy Cat, and Taunt. They've save my butt against land shark for Pete's sake. LAND SHARK!
Large groups of four or more are more likely to get gold than being a solo player and getting your butt kicked, hence why a few friends and I made up The N.A.G., A zOMG clan to help level up new comers.
That's all I got for now, My fingers are starting to hurt... >.