Well, then, your friend didn't teach you how to shoot very well at all!
I recommend taking a class, or at least getting lessons from someone who formally teaches basic shooting on a regular basis.
FIRST, learn the Four Rules by heart and FOLLOW THEM!
http://thefiringline.com/library/safetyrules.html
Sight alignment, sight picture, and trigger squeeze are the basics of a decent shot.
This video gets most things right (disagree with his thumb placement and part of his stance, but those are more preferences than right/wrong).
http://www.youtube.com/watch?v=OMoGzZxdbOE