I am definitely very tankish in my play-style, which isn't a good fit for this game. It took me six hours to beat that boss. I tried so many strategies until I settled on the sneak up behind him, conjure my wolves and then get in as many hits as I could before jumping out of the way and running. But even this strategy failed over and over because he would throw some skull thing at me as I ran away.
The final effort where I got the win was just epic. Sneak in, wolves deployed, got lucky with a great sword knock down, dive away and heal. Go back in while one-two wolves still alive, hit and hit and run, heal. Wolves dead. He is right at 50%. I run and let him agro down and go to his little spot. Sneak up behind and hit him as much as I can and run, run run. Heal. rinse and repeat a couple times. I am down to my last heal and he is down to probably three hits left. I run in the wrong direction and I am now in the town crouched down behind some building hoping he calms down and goes back to his spot, BUT NO!! He literally falls right on top of me!! I about pissed myself and started mashing buttons and killed him somehow. I was sweating and exhausted as this battle took over 20 minutes.
Now I am guessing you all are looking at this going--he is doing everything wrong and yep, I am, but this was a great, fun battle. I don't think since the early days of PC gaming with Ultima have I thought about a game when I wasn't playing it and how I could get over a challenge.
This is a great feeling in this game. Congrats on finally winning. Now go get some better summons!!
Also, yea, you are sort-of playing "wrong" for your build. If you are tanky and heavy, you should be blocking and constantly at the bosses feet, circling behind him/etc (most bosses anyway). Not sneaking and hit and running.
To me, that's the big key to this (and any Fromsoft) game - play to your build. If you are a tank, then tank - get your big shield, and get right in there. If you are fat rolling because of encumbrance, don't even bother - you're just going to take hits. If you are lightly-armored, fast and dodgy, then hit and dodge - don't trade hits.
I see dodge guys get greedy and always take a big hit because they just had to make one more attack. And for any playstyle, having a weapon that properly scales with your main stats is a big deal.