When trying to make positive grade and habits changes there is a dependent relationship between motivation and building a study skills toolbox. Because most schools only teach students a handful of study tools, it is very common for even very motivated students to get stuck.
Often the prevailing wisdom is that we should wait for students to get motivated before introducing study skills. But I have found that students often become more motivated after learning a handful of powerful study tools and techniques. When they have these tools in their toolbox they can make more progress and see the better result with the same amount or less of effort, this is very motivating. These students are then interested in learning more about how to study faster.