Diamond Mind. A Psychology of Meditation.
The image of the diamond its sparkling purity "is suggestive of the ever-present enlightened mind which is within each one of us. ... It goes further. The diamond is the hardest of gems, and manifests an adamantine quality. Its power serves all obstacles----nothing can withstand its sharp strength. For us this is the most encouraging news----although our diamond minds may seem to be enmeshed in a tangle of obscurations, we will surely cut free!"

The Four Foundations of Mindfulness (p.32-p.35)
(1) Mindfulness of the body.
What is happening in the body?
Do we know?
The body is continually affecting our mind states.
(2) Mindfulness of feelings.
The sort of feelings that ripple throughout the body, but that aren't completely physical. They relate to the impact of emotion on the body.
What am I feeling emotionally?
Learn to be OK about our feelings. Acknowledge that feelings are happening.
(3) Mindfulness of the mind and its states.
What sort of thought patterns, what sort of mood am I in?
What is the mood? What is my overall mind state?
We begin to discover that mindfulness can be clarified simply by knowing that there are separate areas from which it is affected within the overall movement of the psyche.
(4) Mindfulness of mental contents.
This usually relates to our overall picture of the world or our philosophy of life.
They help the mind free itself from the bondage of grasping.
Conversely, mental contents may lead us to bondage. If they arise and we dwell on them, act them out, or in some other way feed energy into them, they increase the state of bondage.
一切有为法,
如梦幻泡影,
如露亦如电,
应作如是观。
《金剛經》
This is really a lifelong practice, isn't it? :)