here's another tip I did few years ago...

- in advance position the door pocket on the door panel to where you want
it, put some chalk marks for positioning
- take some screws and put them on the door pocket
- dab some latex paint on the head of the screw
- position the door pocket on the chalk marks and press - the paint will
leave marks for drilling the holes
- drill the hole on paint marks
- remove the screws and attach the door pocket from the other side of the
door panel.
- do not force on the screws because the screws bosses may brake - if they
do then use JB Weld to fix

:-)