One thing I have experimented with in my teaching is the use of FAQ (frequently asked questions) documents. As I admit to the students, I deem a question to be an FAQ if it is asked more than once, or if it is asked once and I think it is interesting enough to be useful to others!
Students do often come up with the same questions year after year, and so this can be an efficient way to help them: I have had some very positive feedback from the students on this.
It is important that the FAQ documents should not grow so large and unwieldy that the students are reluctant to look at them. Nor should they be a substitute for clarity in the lecture notes!
One of my most popular FAQ documents was for the module Complex Functions, which I taught in 2003-4 and 2004-5. I used my colleague Jim Langley’s excellent lecture notes for this material, but added a Complex Functions FAQ document of my own which gradually expanded over the two years that I taught the module.