I have taught some of my students the hammer technique and it depends on the student and their experience as to how fast they latch on to the technique. For a beginner they lack the hand strength and finger independence required so building the pull offs is where I usually start and refine that.
I that case trill exercises usually work best for building hand strength and synchronicity. The real trick is keeping everything in time with an even tone. I find that some players pull off to hard causing the intonation to go out.

Peace,
Joe

http://www.joepinnavaia.com