Melanie R. Kuhn's Hotsheet 3: Effective Practices for Reading Fluency does a wonderful job of quickly outlining the essence of fluency instruction. It points out ineffective (round robin and such type practices) and effective examples (challenging materials, echo reading, choral reading, partner reading, and reading-while-listening) of fluency instruction. It has a rubric for evaluating reading fluency of students. It also highlights components of effective instruction: modeling, practice, challenging material, wide reading, and repeated reading.
What I found especially important to recall is the definition Dr. Kuhn uses for challenging reading. The Common Core standards use the term challenging reading, but it is not defined. Most people interpret it as material at or above grade level. Kuhn's definition is material that is read at 85-90% accuracy on the first read. For approximately one-third of all students, this is material below grade level, sometimes far below grade level. In order to develop fluency, students need to practice on material that is at their instructional reading level. While exposure to readings at and above grade level can develop vocabulary, background knowledge and listening comprehension, developing fluency which will in turn develop reading comprehension requires readable material.