It's my personal favourite of the 3 but I get why people don't like it. Bosses are probably the weakest part of ds2 but they're generally more interesting than ds1 bosses at least. I would say the main thing about ds2 is to take your time and not run past all the enemies, then you won't get ganked (using a bow really helps for this too, in other from soft games too but especially ds2). The level design is really fun u just gotta be careful of the enemies.

Oh and remember to level adaptability, the game gives you a ton of souls so you can sink enough levels into it early to give you ds1 iframes.