My early tries at kheer were thinner than I wanted, and the texture just wasn't great.  The way I've made my kheer lovely & thicker with a creamier texture came from a few techniques Chetna's recipe gave me.
The first is crushing the rice so it's in small even pieces, letting it thicken evenly.  The second is not starting with ghee and rice, but rather by heating the milk.  Thirdly, using sweetened condensed milk rather than just sugar.