I just read all of the replies, and they all have merit.
First though, it helps to have good speed coming up onto a coping grind. Going too slow makes it hard to maintain your body over the grind. Use good pads and crashing won't be a factor in your attempting more speed.
Second, As Claudine said, practicing in a bowl will be easier to learn than on a street course or half-pipe. Wooden bowls are the best! Not as painful learning as concrete can be. :Þ~
As Joe said, try stalling and not sliding first. Helps to condition brain to accept odd foot placement before going for the grind.
As Zorg said, upper body and body part(s) orientation helps to direct the feet. Play with it, and figure out which different body movements make any trick you do easier or better. This is never the same for every skater. Everyone finds their own style. Always keep your body relaxed, flexed, and balanced. Bent knees, elbows, and waist will help you keep your center of gravity.
Additionally, try just skating flat-street with your skates heel to toe while following a straight line on the ground. Figure out which skate is better to have in front. Which skate better while going right or left. I find that going right means having the left skate in front, while going left means having the right skate in front. This allows you to come out of the grind with your skates already in position to go back to a parallel stance!
And finally, nothing beats watching others, or finding videos of others, doing what it is that you want to learn! Dissect what it is they are doing right and replicate their actions.
: Hey All. Well after Buba's photos, I'm embarrassed to even show this but I know a couple of you asked me for it so here's installment one of my limited progress on truck grinds.
: I continue to have difficulty arresting my rotation to only 90 degrees. My body wants to turn 180. So far, I've only been able to get 1 skate on the coping with the other skate rolling on the platform. Not REALLY grinding, but I'm getting the feeling of my trucks on the coping. Which is ALOT different feeleing than my ghetto grind "plates" I made for my old skates. So anyway, without further excuses here are a couple of video clips from last weekend of me trying.
: This is about a 4 foot tall 1/4 pipe I'm trying the grinds on: