OK, there is a REALLY EASY way to kill dragons!
Spoiler:
Buy Summon Demon scrolls from Gorax in Monastery (you can find them also). After talking with a dragon run a little aside and summon a demon (immune to fire and a hell of a fighter!) who immediately attacks the dragon. In five second the dragon is dead (you can help a bit), you get all loot and thousands XP.
The Swamp dragon is the easiest. No need to summon demons: take Rod and Cipher with you. The Ice dragon is the toughest.
Man's most valuable trait is a judicious sense of what not to believe.
-- Euripides
Good idead.
I like to summon a Wolf in chapter 2 at each Dragon and while they chase the Wolf you rob them 2 chapter early.
Trust me, most of the names I have been called you can't translate in any language...they're not even real words as much as a succession of violent images.