Select books that are designed for a sixth grade literacy level. The backs of middle school books often contain the recommended reading age for the material. Readers that are struggling should be given a book at the fourth or fifth grade level to start and then they can work their way up.
Assign a chapter a day and then discuss the chapter the next morning with the students to verify that they understand what they've read. Speak to each student individually if you can and ask a few questions about the material to see how each student responds. Practice makes perfect and the more the students practice reading, the better they'll be at it.
Give the students book report assignments where they submit written assessments of the books they read. Book reports are commonly used at a middle school level and this forces the sixth graders to write, which also improves reading comprehension.
Play audio books for the students while they read along. Hearing the text while reading it assists sixth graders with overall comprehension, especially if they are struggling.
Increase the reading level of students who are doing well by assigning them books that are intended for seventh, eighth or ninth graders. This further challenges the students and encourages them to continue improving. The more complicated stories and varied vocabulary help prevent the students from becoming complacent.
Recommend a reading tutor to students who continue struggling with sixth grade reading material to help get them up to speed. A personal tutor helps keep a student motivated and identifies specific issues with that student that negatively affect the student's reading ability. A tutor helps recognize problems such as dyslexia or attention-defect disorder that require professional intervention.