For Adults:
If you are new to Mindfulness or meditation practices in general, here is a good place to start:
Jon Kabat-Zinn is the creator of Mindfulness-Based Stress Reduction (MBSR). While MBSR is based in Buddhist meditation practices, Kabat-Zinn places less emphasis on the spiritual dimensions and a greater emphasis on how these practices can reduce and control stress and anxiety. These three resources explore MBSR.
Tara Brach is an internationally known teacher of mindfulness, meditation, and emotional healing. She is the author of Radical Acceptance, True Refuge, and Radical Compassion. The following website and videos provide a view of her four-stage RAIN (Recognize, Allow, Investigate, Nurture) meditation and Mindfulness practice.
https://www.youtube.com/watch?v=y3TrGysWETw
https://www.youtube.com/watch?v=XZPgWSyYOlY
Daniel J. Siegel, MD, is an internationally known clinical professor of psychiatry and a co-founding director of the Mindful Awareness Research Center at UCLA. He has published extensively on Mindfulness, both from a practical and clinical perspective. He has also published five books on parenting from a Mindfulness approach. Here is a list of resources he recommends:
https://www.drdansiegel.com/resources/
Thich Nhat Hanh is an internationally known Buddhist scholar and monk. He was one of the first exponents to bring Mindfulness to a western audience. These meditations emphasize the spiritual as well as the interpersonal dimensions of Mindfulness.
https://www.youtube.com/watch?v=BzA6Hu840to
https://www.youtube.com/watch?v=b5gMJ1BovQ0
https://www.youtube.com/watch?v=sb8DAYK81Oo
This website describes a local (Northampton) organization dedicated to the study and practice of Mindfulness. They offer various programs, courses, and list other resources.
https://valleymindfulness.com/
For teens:
The following websites discuss Mindfulness-based stress- and anxiety-reduction as it relates to teenagers. Many of them offer activities and exercises to help reduce the types of stresses and worries that teens typically feel.
https://www.stressedteens.com/stressed-teens
http://theanxietylad.com/27-mindfulness-exercises/
The following interview with Gina M. Biegel discusses many if the ideas contained in her book, The Stress Reduction Workbook for Teens:
For children:
Mindfulness is an approach that is increasingly being used with children, both inside the classroom and out. The following resources discuss its benefits, suggest various activities appropriate for this age group, and also mention certain critical perspectives.
https://positivepsychology.com/mindfulness-for-kids/
https://childmind.org/article/the-power-of-mindfulness/
https://www.nytimes.com/guides/well/mindfulness-for-children