When you show your students that you believe talking with skilled readers about their writing is important, they're much more likely to pursue it. One way to begin this is with a blurb in your syllabus about the Hixon Writing Center.
Here is a shorter and longer blurb you might include in your syllabus. Please feel free to adapt or edit them in any way that suits your needs:
Shorter blurb
Caltech's Hixon Writing Center offers a number of resources that you may find useful for supporting your writing in this class, including tutorial support that allows you to discuss a work-in-progress with a professional or peer tutor. You can learn more about the location of the Hixon Writing Center, how to make an appointment with a tutor, and about their other resources on their website: writing.caltech.edu.
Longer blurb
Caltech's Hixon Writing Center offers a number of resources that you may find useful for supporting your writing in this class. Its primary asset is a team of trained professional and undergraduate tutors who are available to read and discuss your writing or to answer specific questions you may have about academic writing. A meeting with a writing tutor is a dynamic conversation with a smart, careful reader. Tutors don't "fix" or edit your writing for you; instead, they help you think about and implement strategies for improving it yourself. This kind of conversation is the primary way in which both novice and expert writers improve their ability to communicate in writing. You can learn more about the location of the Hixon Writing Center, how to make an appointment with a tutor, and about their other resources on their website: writing.caltech.edu.