Generally I begin with prayer to the Holy Spirit, asking him to help me pray and keep me free of distractions.
Then I proceed to vipassana, clearing my mind of all thoughts and just focusing on breathing and the true presence of Christ in front of me.
I then sit in a state of zazen, with my mind open for whatever the Spirit leads me to consider, if anything at all. If not, I continue to focus on breathing and Christ's true presence.
The only time when zazen is true is when you aren't looking at your watch and are prepared to do anything the Spirit asks, even if it is to spend the rest of the day in meditation.