is there a right or a wrong way to install spark plugs? Do you just screw them in, or is there a given amount of turns you need to do?

I don't have my manual with me...but I think it said it should be torqued at 8 or 9 ft/lbs....and if no torque wrench is available then had tighten by hand and then use the wrench and turn 1.5 times....

I'll check the manaul later when I get home to be sure....

what i do is go as hard as i can with my hand,then use a ratchet and tighten for no more than1/4-1/3 turn.
1.5 is dangerous to strip the head,and we all know what it means.

just lightly tight.