An easy method of self-assessment that you can quickly and easily set up in your classroom consists of 3 drawers (I have a red drawer, a yellow drawer and a green drawer). Stick these labels on the front. At the end of every lesson, pupils place their book or sheet into the drawer to show how they feel about their understanding in that lesson.
My labels can be found here: http://www.teachingessentials.co.uk/classroomlabels2.html
This helps you to assess learning, reflect on the lesson and plan for future learning opportunities. You immediately have an idea of who needs further support.
These work most effectively in an environment where pupils are regularly self and peer assessing and aren’t scared to admit that they need more time on a specific area.