Unsurprisingly, DBT shares some principles in common with Mindfulness-Based Cognitive Therapy. (They also have their differences.) This link takes you to a four step mindfulness practice for changing patterns of negative–or otherwise ineffective–thinking designed by Elisha Goldstein, PhD. The principles will be familiar. Mindfulness of thoughts, naming, observing sensations in the body. See if you find it helpful–bearing in mind, as the author says, that the aim here isn’t necessarily momentary reluef; it’s to change pervasive habits of thought that may be getting in your way.