Dark Souls it the spiritual successor to the most difficult game ever made, Demon's Souls. The keys to progression in this game are to pay attention to your surroundings and even more importantly, learn from your mistakes. It's also a good idea to have something you can punch handy. Might I suggest a pillow or perhaps a little brother? I'm joking of course, my younger brother could kick my ass.
Dark Souls comes out on October 4 for the Xbox 360 and PS3.