There were two ways I fought every dragon. Most them I could eliminate with a mage, from a distance the dragon didn't engage me from, shooting at them for half an hour. Shameless, I know. But, I couldn't really be bothered micro-managing combat, which took equally as long. However, WHEN I was forced to fight them head-on, I did so
without using even one healing potion or any other potion. I never used potions in any Dragon Age titles, before. I was only forced to use up two in that fight with that guy in the temple, after the time-traveling mission, at the end of the first Act 1 (if I got that right) and only towards the end of the fight, on my first play-through.
By micro-managing EVERY step of every character, I took down everything without having to spam healing potions like a god damn amateur.
With friendly-fire. So even positioning my party to not hurt one other was something I had to pay careful attention to. In subsequent playthroughs, I did start using potions, just to try that approach and found it made the game nearly effortless. I'd wager I could've beaten the game on the hardest difficulty, too. If I wanted. But, I saw no point in doing that. I'm a
filthy casual.
The easiest I've ever had it was with the specialization that gave me that magic blade attack for my mage. I built it so that with every strike it refilled my barrier and later even my armor, which made me almost invincible, I still didn't dare take on attacks directly and had to position myself accordingly, but I could slash away at everything and do quite decent damage. I loved getting up close and personal and go mad with my femme.