Umm...
I hate to be the party-pooper, but I fear you won't get a detailed answer to that either.
But let me give you a push into the right direction... most of the trainers are in the cities, the low level trainers mainly in Hydlaa (the city with the plaza, the big fountain and the red temple) and Ojaveda (the city with the desert-like look, which is normally packed with kitties [Enkidukai

]) So, just walk around a bit and check every NPC you see if he/she is a trainer, by right clicking them.
Edit: Yay, now Caarrie is the party-pooper for answering first
