Do your students write sentences that start with because or if and think they are complete? My seventh and eighth graders had a big problem with this, so I created a lesson on subordinating conjunctions. In one 45 minute class period, this issue was mostly resolved.
Download this power point for direct instruction on subordinating conjunctions, paired-practice, and a handout that can be printed for students to keep in their Writer's Notebook for their reference.
Teacher and student directions are written in the notes of the Power Point. Answer key is also listed there.