The booklet says to tap the x button, but that just doesn't seem to work. I try tapping it as early as possible (and as late as possible), but to no avail... Does anyone have any pointers on how to execute headers? I mean ANYWHERE on the field, not just off the corners, etc.

you must hold down the button. i was lost too for a while but i learned. hold down the button and the direction you want to head it. i scored many more goals than before after i learned this. o is for shooting and x is to the ground. d is a "lob" header.

at fist i hit buttons like a mad man when teh ball came ot me, but i learned, i re-made the german world cup team

I did the same to my countries team, Brazil became a power house