If you have maybe 10-15 minutes, look through these slides. There are many, but I think you will find some value in the information and the links off of the slides! Some of the information may not be relevant but I enjoyed most of it!
The definition of Differentiated Instruction! Even when you level your instruction or focus on a concept for an extended time with some students, all students need to be able to take something from your instruction. It takes a lot of planning and management, but it is completely necessary if you'd like all of your students to benefit from each lesson in some way.