Getting feedback from students is the best thing you can do to improve your craft as a teacher.
I end every week with an exit ticket (and the course as a whole with one), and it is often the highlight of my week reading students' responses. I tell students that feedback from me is the way they improve as students and so to is their feedback the way I improve as their teacher. Understand though that the motivation of your own growth should always be improvement in student learning.
Include several straightforward questions about the relevant subject matter. These are ungraded "formative assessments." In other words, these are means by which you can see if your students actually understand what you taught them. It is no good for students to enjoy your class but not actually learn anything, and just because you taught it doesn't mean they learned it.
For example, if you are teaching the binary number system, give them a few small sample conversion problems to answer on the form (and yes, Google Forms is my absolute favorite and preferred means for gathering and analyzing this data, but you could certainly do this without them). See if they can actually do what you have been teaching. I would then follow up these short practice questions to test for understanding with questions such as the following:
- In terms of my instructions, what worked and what didn't?
- Are you comfortable with your ability with this week's subject matter?
(Using a Likert scale is handy - I remove the "Neutral" option, so students have to "pick a side.")
- Comment on the pace of instruction.
- Did I provide you with sufficient examples?
- What questions or comments do you still have about the material?
- The objective of today was for you learn X. Do you think that goal has been achieved?
There are great resources on exit tickets online. A quick Google search for "exit tickets" will give you some great examples. This page from Brown University has more sample questions.
Note on anonymity: None of my surveys is anonymous. I work hard to build an environment where students know I am actively working hard to hone my own craft and that I trust them and am humble enough to reflect on their feedback. I've had many occasions where following up with a student is necessary to make sure I can respond appropriately to their feedback. Students respond positively when are invested in their respective; if you show you are working hard for them, more often that not, they work hard in return.