For the medium size ones, I usually either, use Cynder's shadow or Fear aliments, or will go with Spyro's electric or fire breath to wear them down and then go in with some standard button smashing.

For the Huge Ogres and the Trolls, basically the same the same thing for the medium ones except I go with Cynder's poison breath and Fear and use hit and run tactics. That or I will just switch to Fury breath and take'em out like that.