Hands on application of any learned skill is critical to making meaningful connections; and math is no exception. I invite you to look at some projects I've put together; I am often asked 'why do we need to know this?'
Why unit rate? Finding the best deal is something that middle school students can relate to, and many food shop with their families. This quick Unit Rate Shopping project piques student curiosity, almost like solving a riddle. Students feel both empowered and accomplished when they are able to find the best deal, and back it up with their math.
Why percents? They have a major impact on our lives in so many ways. I think that both income and major purchase decisions bring this point home nicely for 7th grade students, so they pick an occupation and salary out of a hat, then complete this Real World Percentages Project.
Taking ownership of one's learning is a skill that middle school students need to develop; but it's a process, not an event. I try to assist in that journey by having my students set their goals at the beginning of each term, and then write a Portfolio at the end of the term. They are asked to provide evidence of their work, discuss specific problems, and reflect upon their term as a whole. I encourage them to discuss both developmental strengths and needs.