Focus on the hard stuff. I remember early on in my teaching career realizing that while I was doing a pretty good job getting students to read and discuss literature, I was not really teaching them writing. So I decided to schedule the block day in our week as a writing day. Ten years and thousands of pages of creative writing later, I still had not successfully taught my students to write a research paper, so I blocked out three full weeks in our schedule to work through the process from beginning to end. Rather than focus on what I know is humming along fine, I look for the weaknesses. Usually, these are the areas that don’t come naturally, or that I don’t like very much myself. (And I still sort of despise research papers.) But when I focus on the hard stuff, I am a providing a much better learning experience for my students.
This is such an important part of sustaining yourself in a career like teaching!