I know most people like to figure stuff out on most things, especially this game (it's half the fun) but I would recommend the demon's souls wiki for enemy strategies and what not it helped me immensely, i believe I'm currently on my 5th playthrough now and loving it.
My own advice, don't worry about the heavy armor, stick with leather it allows you to dodge roll very quickly and if you make it to New Game+ you'll see why dodge roll is a necessity. a normal mob arrow can insta-kill you in NG+, heavy armor or no.
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I am so omniscient, if there were to be two omniscience's I would be both! Prepare yourselves for the subjugation! - Ziltoid The Omniscient.