The gameplay has been completely overhauled from the original and is now over the shoulder with free aim. The best advice I can give for a newbie at the start of the game when using the handgun is to wait until the aiming reticle locks into place and go for headshots, waiting for the reticle locks before each shot, then when they drop use the knife to make sure they stay dead. Do not assume zombies are dead when you run into ones who are still and to slash at them with a knife to make sure so they don't come after you later when it's less convenient. Also, make the best use of wooden boards when you get them and be sure to backtrack and place them on the windows, or you'll regret it later.
Experts will eventually learn how get past zombies by shooting them in the leg until they are stunned and then running past them but that's probably on a later playthrough on hardcore when you're trying to get a better rank. Also, best to save grenades and heavier weapons for bosses, but that's probably pretty obvious. Lickers can usually be avoided by walking past them and not running or touching them. When you run into Mr. X, if he's on top of you try to head for a save room until he goes away and also gunfire attracts his attention.
I think this is a good starting point and you should learn things on your own as you progress in the game. Good luck and enjoy one of the greatest remakes in gaming history.