During my experience in a MBSR Group I was advised to read the books by Jon Kabat Zinn and I was so glad that I did. Below is a guided sitting Meditation by the man himself. You can also find him on youtube for free.
Guided Sitting Meditation
This guided sitting meditation will help you learn to simply be and to look within yourself with mindfulness and equanimity. Allow yourself to switch from the usual mode of doing to a mode of non-doing. Of simply being. As you allow your body to become still, bring your attention to the fact that you are breathing. And become aware of the movement of your breath as it comes into your body and as it leaves your body. Not manipulating the breath in any way or trying to change it. Simply being aware of it and of the feelings associated with breathing. And observing the breath deep down in your belly. Feeling the abdomen as it expands gently on the inbreath, and as it falls back towards your spine on the outbreath. Being totally here in each moment with each breath. Not trying to do anything, not trying to get any place, simply being with your breath.
You will find that from time to time your mind will wander off into thoughts, fantasies, anticipations of the future or the past, worrying, memories, whatever. When you notice that your attention is no longer here and no longer with your breathing, and without judging yourself, bring your attention back to your breathing and ride the waves of your breathing, fully conscious of the duration of each breath from moment to moment. Every time you find your mind wandering off the breath, gently bringing it back to the present, back to the moment-to-moment observing of the flow of your breathing. Using your breath to help you tune into a state of relaxed awareness and stillness.
Now as you observe your breathing, you may find from time to time that you are becoming aware of sensations in your body. As you maintain awareness of your breathing, see if it is possible to expand the field of your awareness so that it includes a sense of your body as a whole as you sit here. Feeling your body, from head to toe, and becoming aware of all the sensations in your body.
Being here with whatever feelings and sensations come up in any moment without judging them, without reacting to them, just being fully here, fully aware of whatever you’re experiencing. And again whenever you notice that your mind wandered off, just bringing it back to your breathing and your body as you sit here not going anywhere, not doing anything just simply being, simply sitting. Moment to moment, being fully present, fully with yourself.
Now as you sit here once again allowing the field of your awareness to expand. This time, expanding your awareness to include thoughts as they move through your mind. So letting your breathing and sense of your body be in the background and allowing the thinking process itself to be the focus of your awareness. And rather than following individual thoughts and getting involved in the content and going from one thought to the next, simply seeing each thought as it comes up in your mind as a thought and letting the thoughts just come and go as you sit and dwell in stillness, witnessing them and observing them. Whatever they are…just observing them as events in the field of your consciousness…as they come into your awareness and they linger and as they dissolve.
If you find yourself at any point drawn into this stream of thinking and you notice that you are no longer observing them, just coming back to observing them as events and using your breathing and the sense of your body to anchor you and stabilize you in the present.
The thoughts can take any form, they can have any content and they can be either neutral or very highly charged. If thoughts come up that have fear in them, then just be aware of fear being here and letting these thoughts come and go. The same for worries, preoccupations, and so on. Regardless of the feeling that a thought might create for you, just observing it as simply a thought and letting it be here without pursuing it or without rejecting it. Noticing that from moment to moment, new thoughts will come and go.
As the meditation ends, you might give yourself credit for having spent this time nourishing yourself in a deep way by dwelling in this state of non-doing, in this state of being. For having intentionally made time for yourself to simply be who you are. And as you move back into the world, allow the benefits of this practice to expand into every aspect of your life.
Reference: Mindfulness Meditation, CD Series 1, Jon Kabat-Zinn