I've never had to track a deer with a ML- they all have done gone and yielded to the force of gravity right away upon being shot. With a bow- completely different story. I generally watch the deer as long as I can as it is running and remember the last landmark I can see.

I'll then walk to that last landmark (tree, hill, etc.) and start looking for blood. If I can't find blood, I'll start making semi-circles in the direction the deer was last headed. Once I get out a few dozen yards, I'll start making complete circles, looking for blood, hair or tracks. It works most of the time, but not all the time- I've lost a couple while bow hunting, not very fun.