Do an interest inventory to find out what students are interested in, but don't do the typical questionnaire. The goal is to find out their interests, and students reading below grade level may have trouble reading the questions.
Instead, make a bar graph with your students using poster board and post-it-notes. Along the bottom of the poster board, list several student favorites that pertain to your age group. For example, a second grade chart might list cartoons, soccer, reading, TV, swimming, friends, recess, PE, and so on.
Then give students three post-it notes and ask them to write their names on them. Each student takes their three post-it notes to the chart and puts them above their three favorite interests.
The stacked post-its will create a bar graph, so you can also use this as a lesson on reading bar graphs! Which interest is the most popular? Which is the least? What is a good title for the graph?
Once completed, you will have a visual of what your struggling readers may be interested in reading or writing about. If one of your students is interested in bikes, then find a book on his level about biking or trick bikes or motorcycles. Allow him to read this book by himself or with partners depending on his learning style, respond to it in his reading journal, and make a poster or a PowerPoint about what he learned. This can be done while your more advanced readers are in a small group reading a different or higher-grade level novel.