NCTM has undertaken a major initiative to define and describe the principles and actions, including specific teaching practices, that are essential for a high-quality mathematics education for all students.
Link to Ed Week article - http://blogs.edweek.org/edweek/curriculum/2014/04/math_group_releases_guidance_o.html?intc=mvs
Link to the executive summary - http://www.nctm.org/uploadedFiles/Standards_and_Focal_Points/Principles_to_Action/PtAExecutiveSummary.pdf
Link to the page on NCTM’s website about the document - http://www.nctm.org/principlestoactions/