In realistic it's easier to kill more. This won't help you much in normal mode - it's irritating! In realistic you need 3 or 5 bullets (autos) and 1 or 2 shots from other weapons. In normal mode you really have to spray and pray. Personally I dislike normal mode for being too Undead Boss-like, immitating stupid unrealistic fantasy games where you need liek 15-20 bullets to kill a HUMAN.
I guess it won't help you much, it will even damage you and you'll be handicapped in normal mode.
The best thing a noob might wanna learn is: Choose a mode that suits you best. Play more in that mode unless you want your skills getting screwed.