It would help if you let us know what kind of detector your using as different detectors work slightly different on pinpointing.
I have Minelabs and a Whites, both work on using the pinpoint feature and then narrowing down the area as I swing it left to right then forward to backward. On the minelab I can move it slowly forward after doing the X method and when it sounds off target is at the very front of the coil.
On the whites I do the same "X" method on swinging it and target is in the center of the coil at the strongest signal.
Let us know what unit your using and what it does and someone will help you I am sure.
I also recommend a pinpointer. I use one to speed up the recovery so I can cover more area.