Pistol is way too weak
the only weapon i can use effectively is the SMG
so far i use the tactic probing and retreat then fire, usually i try to walk up to dark corner useing flashligh and hear for noise when i saw the threat i move back and fire, be careful cuz there are lot of monster spawn rite behind you
when you go agaisnt human ( possesed) try to use pistol cuz those guy usually dont charge you go for head shot.
when you fight with other monster keep distance and use shot gun and smg. Most monster i saw so far cant do range attack, one of them can throw fire ball and those you can dodge easy.
when you enter new room watch for any opening or some door the monster can spawn from there . DOnt jump, be prepare,be brave

if u panic it will decearse your chance of survival
alway look out for PDA or any eletronic devices. and dont forget to RUN, you will be out number in some occation where 3 or more monsters appear at a same time RUN if u stay u ll die for sure. Run for any open space and throw grenade behind you,