@ Khuutra )
you don't need to "prepare" for Demon's Souls
DS is just a very logical and consequent game ..
your enemies are strong, powerful, often quick and mostly can take quite a beating, but they are stupid, so you have to use your brain to kill the enemies
observe them and analyze their attack patterns, try to pull them one by one and don't lose head while fighting one .. that way the game is actually pretty easy (maybe too easy)
ah yea.. enemies that look strong probably are strong and if you don't feel confident whether or not you should face one (after having progressed deeply into a lvl) then don't and come back later