One of the biggest challenges for creative writing graduate students who are also TAs is time management. Depending on class size and the number of courses you'll be assigned to teach, you could be grading twenty to fifty papers every few weeks. That's a lot of time spent reading, let alone grading. TAs also are usually required to hold office hours, which are more time spent away from your own creative endeavors. From the beginning, work to develop a schedule for grading papers. Get a sense of your own rhythm and endurance: How many papers can you read before you begin to glaze over? What is your best reading time? What is your best writing time? Once you have a sense of this, make a schedule that is most productive for your working style and be vigilant about sticking to it. While grading takes time and energy, so does worrying about the huge pile of papers you've let build up on your coffee table.
Most programs have established methods for determining how well you're performing in the classroom. Some institute peer visits during which fellow TAs attend one or more of your classes and give you feedback on how they think you're doing. These can prepare you for formal assessments, during which a faculty member observes your class and later submits a written evaluation to the department under which your classes fall. Finally, your students usually have a chance to weigh in through end-of-semester evaluations, which are also submitted to the department. Such evaluations are usually shared with you. Take any feedback you receive seriously; there's always room for improvement. And a poor overall evaluation may threaten your receiving a reappointment for the subsequent year.
Being a TA is a serious and important responsibility. Doing it well often draws from the same energy source that feeds your own writing. So it's crucial to strive for balance between doing your best in the classroom and at your writing desk. But having teaching experience under your belt can be a tremendous boon postgraduation. If nothing else, it gives you a sense of whether teaching is a career path you want to pursue. The skills you learn along the way can also be applied to other occupations that involve leadership, the training of others, and public speaking. Perhaps most valuable, being a TA gives you the chance to help cultivate a wider appreciation for writing, and reading, in the public at large—and to build the audience for your own future contributions.