I did a CNJ crossbar setup video: http://youtu.be/mT53s-XNxWI
Even if you aren't using a gamepad, I explain the reason behind skill locations for "rotation" style positioning.

Basically when I'm healing, I'll shoot off an aero and thunder right off the bat to do some damage over time while I heal. If I'm not healing, just soloing, I still start off with aero (damage over time) then move into some stone.

Depending on the situation, I might shoot off some thunder or ruin within that pattern.

Sometimes I even start out with aero, thunder, stone, then ruin... of course I'm in cleric stance for offensive bonus and I have my healer chocobo out...

Hope that helps.