It seems that you're using an outdated browser. Some things may not work as they should (or don't work at all).
We suggest you upgrade newer and better browser like: Chrome, Firefox, Internet Explorer or Opera

×
I'm talking about the dragon, not the later boss fight.

Anyways, here is what I figured out:
-Have a really really good silver sword, youll only get like 1 blow off at a time.
-MAKE SURE YOUR QUEN SIGN IS UPGRADED ALL THE WAY. It gets a 2:00 timer so you can usually absorb 2 hits.
-Combat roll in, slice it's face once, then combat roll away quickly. the "Feet Work" trait helped for this.
-Don't get greedy with hits. Take your one hit and keep quenning. It's a long, slow grind of a boss battle.
-When it is in the air, run around and recharge your quen. It's easy to dodge it's swoop attack, and as long as your on the far side of the platform it won't be able to set you on fire

Thats about all I picked up. Best of luck guys.
I'm in the middle of that fight as well, figuring out your suggestions the hard way (for Geralt). Gonna have to make do without the upgraded signs, though. Thanks for the post! :)