Easy to digest research on Mathematics education from Cambridge Mathematics, see their Espresso page where in their words, “Each month we bring you an Espresso – a small but intense draught of filtered research on mathematics education, expressly designed with teachers in mind. Each Espresso considers one particular issue in mathematics education, and how the latest good-quality research can provide helpful guidance or further reading.”

The following references are not specific to Mathematics but I believe are important for teachers of any subject.

Teaching and Learning Toolkitfrom the Education Endowment Foundation; they describe the toolkit as “An accessible summary of educational research on teaching 5-16 year olds.

What is Worth Reading for Teachers Interested in Research?
Professor Robert Coe’s list of sources of educational research for teachers. These are things that Professor Coe considers are worth reading. He states that they are all relevant to teaching and/or school leadership and present high-quality, sound research.

Really important – talk to your students about how to study not just what to study.
A subject I am fascinated by and feel is very important for students of all ages. I believe that Retrieval Practice for example really helps students. For some work I have done and my students’ view see Low Stakes Testing in the Mathematics Classroom.

For valuable resources to support the techniques described here see the excellent downloadable materialson study strategies. Note how each strategy is backed up by research.