Like if you're defending or if you want to catch an enemy lurking, how do you hold an angle so that you can kill enemies easier? ( I also have trouble with off angles as well )

This is just my opinion but everytime I watch ACE clips there's always a few that say "Let me get the ACE" right when I hear that then it loses that clutch/wow feel. And I think that an ACE is more rewarding when you're not asking for it....