Wow’s system is based around random loot tables, so most of the times you won’t need Tibia Gold to target a particular mob.
Occasionally you can find a “phat lewt” mob that respawns randomly every 8-24 hours that always drops good items, but these are few and far between and you won’t normally see them. They really aren’t worth camping.
Grinding out items is boring, but can make you gold, especially when you reach around level 50 and even poor drops can sell for 1 gold. The very best way is to do instances; they have the very best drops and can earn the most experience. Of course higher level characters should do higher level instances.
However, grinding gets boring sometimes, so you can also mix it up by doing some lower level instances, sure the rewards aren’t as good all the time, but they can yield some good blue low-level items that you can sell for a few gold and there are some cool scripted events that will reduce the boredom factor.
Herbalists should grind monsters in the open or troll shamans who have the chance of dropping wild vine while tailors should generally stick to humanoids.