The tactics level of the animal you're fighting needs to be within 20 points of the tactics level of your unicorn to get any gains. If it is outside that window, tactics will not move. Go fight the zombies, skeles, and spellbinders in old haven until your tactics hit 50ish, then move outside the city to tangle with black bears, brown bears and grizzly bears. After that find the ettins and kill them for a bit. Once you're tactic hit 70ish you should be able to gain on a lot more things.