door striker adjustment

[batboy]

Help me figure out how to adjust the round door striker post. Maybe they need replaced too as there is a flat worn spot on the top end. I wonder if I can rotate them so the worn spot is out of the way. Half the time the door only closes part way. Seems like I have to slam the door harder than normal to get it to latch all the way. Don't you just loosen them up with a torx socket and then adjust that way? Which direction does the striker need to be moved to take the play and rattle out? I'm assuming in? Luckily, there doesn't seem to be any up and down movement in the door hinge pin. I don't think the door is sagging. Thanks.