The best way to address a wide range of skills in a classroom is to make sure that the learning is leaving room for everyone's preferences. Teachers should design lesson plans so that there is something for everybody, regardless of learning ability or skill set.
Lesson planning is the key to being inclusive with any population of students. Teachers need a clear plan and to make sure to illustrate what extra supplies or time one might need for any group of special learners.
Teachers must make it clear that they are accepting open-ended feedback about the way the classroom works and how they are administering the material. Students know more about learning than teachers do, and it can be very helpful to hear what is and isn't working.
Teachers can separate groups to save time and to let the students work more efficiently. In order to make this process non-shaming for the less-abled students, teachers should put an emphasis on them and let the students who are ahead go off on their own.
Making both skill levels comfortable is key. Learning can be a difficult and embarrassing process with someone with a different skill level. Teachers need to be gentle and keep an eye out for any bullying or harrassment, no matter how minor.