Tricks of griling kabab
I've got a few suggestions on things to try:


If you're using metal skewers you might like to consider switching to wood / bamboo instead. I've never been that keen on metal skewers for that very reason.
I've noticed that sometimes I have a tendency to lift and rotate at the same time so I'm starting to turn while some of the food is still in contact with the grill and doesn't turn. Make sure you lift them well up and then turn gently in a separate motion.
Although just about everyone says to soak wood / bamboo before using so it doesn't burn for things that are fairly quick to cook I often don't and that seems to help as well. You'll need to be careful it doesn't catch direct flames doing it that way though.
For things like chicken that you want to cook thoroughly I normally leave the hood down for most of the cooking and getting some extra heat from all directions reduces the number of times you'll need to turn them.