First off, there's this thing you can do which are summons. They make you invincible for a bit as you summon the whatever. There are two I use a lot, Cockatrice and Unicorn, the first because it does a lot of damage, the second because it is (by far) the fastest way to heal.
Dracula's first stage is wimpy. He has a few attacks that do maybe 50hp damage, but mostly he just stands there and sucks at you (so to speak). His attacks are also almost perfectly timed so that it's trivial to be in the middle of a summon while he's doing them, which, coincidentally, is the only point at which he can be hurt. I've beaten his first stage four times now and I've never been scratched.
Dracula's second stage is tough. He's got three different attacks, Blobby Things That Do About 150hp Damage, Things Falling From The Sky That Do About 250hp Damage, and Big Lasers and Flames and Stuff That Does Around 320hp Damage.
Dracula's third stage has one attack. Run Into You Real Fast And Do About 600hp Damage.
Now, the *last* time I beat him, I was a class that had higher defense and better armor and all those attacks did about 2/3 of the damage they're doing now, plus I had about 1200hp.
Now I have 450hp.
Note the amount of damage "Run Into You Real Fast" does.
So basically, I'm running around healing, hitting him when I can, and eventually getting unlucky and splattered across the landscape.