At the end of every math lesson, my students sit and reflect on the day's work by completing a quick writing assignment. I role these each out individually at the beginning of the year, beginning with What I learned... and Explain what I did and why. We focus on those for about a month before moving on to the others. (**They need explicit teaching on how to write.)
The writing and discussion portion of my classroom directly relates to the CCSS Math Practice standards.