If you aren't already using it, this is a quick tip that might save you a headache. If you are setting homework or tasks based on a digital resource that students (or cover teachers!) need to access online, your best friend is the custom URL.
For example, today I asked my year 11 English cohort to access a particular youtube video at home and make some notes. Rather than foolishly ask them to copy down search terms or (heaven help me) a youtube url and risk misunderstanding or worse, I just went to tinyurl.com, pasted the url of the youtube video I wanted them to look at into the text field and then chose my own custom alias and hit the 'Make TinyURL' button.
It's pretty idiot-proof, but here's what it should look like:
Provided your custom alias isn't already taken, it will make a shortened URL according to your specifications. I usually use my surname and the topic, or sometimes the date. This makes it easier for students to parse and write down correctly. If it is taken, no sweat, just go back and try a variation.
This is one of those time-saving tricks that seems minor but can really save your life. If this had existed when I was in high school, my hapless AP Government teacher probably could have avoided accidentally sending 30 teenagers to a rather seriously startling website when she meant us to wind up at the official homepage of the US White House.