In my experience, the 30-40 range have a ton of quests to manage so the 5% exp/quest never really became an issue. Stacking Guild Quests, Dailies, Book, and main quests and turning them in all at the same time will give a load of exp, plus some spare cash and some loot you will need. Also, try to join others in killing Zone Elite Monsters because they give defender boxes that will give you tokens you can exchange for fame and an exp boost. (You will know they will appear when your notifications say so. They will appear as skulls on your minimap)
I farmed most of my money for gear in that level range. Amacle was right in saying to farm the dinosaurs in case you're bored. The terrified thoughts and items that drop from them (esp. rings) will net you a good amount of gold.
If you find yourself getting bored with playing the game alone, find yourself a guild. Levelling is easier and more fun if you have people to talk to around