The first time I beat the game I used a ranged character, keeping your distance from enemies while shooting them from a distance makes the game a lot easier, some of the hardest bosses become pushovers. For my second playthrough I went with melee (faith based character + moonlight sword which is one of the deadliest builds in the game). Defeating those bosses by getting up close and personal was even more satisfying specially considering the increased the difficulty of new game+. There was a point though where I thought I couldn't do it, I was stuck on the 1-4 boss for months and I couldn't even use the trick we discussed above because I had already done the Mephistopheles quest and couldn't change my spells anymore. Fortunately I had warding equipped so eventually I decided to bet on that, I had no idea it would reduce damage so much and it ended up making the fight a lot easier. I actually ended up jumping and screaming when I beat that fucker, the joy of overcoming the bosses in this game is without comparison.