When I start a new tamer character with 50 taming and 50 magery skill, I usually get very nice taming, lore, vet and magery gains by using the critters I'm taming to kill another critter of the same type. To start with, I tame two of the creatures (e.g., brown bears), release one, and then have the one that is still tamed kill the one that I just released. Because they have more or less equal skills, it usually takes a bit of work for the tamed critter to kill the released one and the lore and vet gains from vetting the one doing the killing stack up very nicely. I usually have the tamer try to help out with the killing by casting whatever magery skills she can cast so the magery gains go up.
After I tame the next creature, I release the one that did the killing the last tme around. Thus, no creature sticks around long enough to really train up skills to any degree and always takes a good beating that needs lots of bandages to heal.
When taming skill is high enough to tame a unicorn or nightmare, I don't release the one that's doing the killing. Rather, I keep training it by killing off the unicorns I'm taming for gains and have released. (No karma loss for killing a released unicorn or ki-rin.) For variety and to make some gold, I'll often take an unbonded unicorn to the wisp dungeon to kill wisps. Vet and lore gains are good and I make some gold. Don't usually try the paragons until the unicorns at least partially trained and/or bonded. However, if an unbonded unicorn dies to a paragon wisp, it's really no big deal to go get another one.
If you have a pair of bonded unicorns or nightmares, take them to kill ogre lords. Or if you have just one that's bonded, kill ogre lords with it and cast an EV to help. You'll get decent vet/lore gains and can build up some honor and make some gold at the same time. And it's a heck of a lot less boring than just standing and having two pets fight each other and keep vetting them, wondering the whole time whether someone's going to come along and report you for doing stuff in-game while being unattended.
I will tame another Uni and try the Ogre Lords That sound like fun.. I'll try not to fall asleep doing that...