Over the years, Instructables has grown and evolved to a site that is both an invaluable resource and a powerful tool for teachers of many practical subjects.
This Instructable is mainly aimed at teachers of all kinds, but students can read it as well, then pass on ideas to their teachers...
All pictures are sourced from either the site itself, or Wikipedia Commons, or created by me, unless otherwise stated.
Step 1: Sign up!
If you use your school email account to drop a line to teachers[at]instructables[dot]com, and let them know that you are actually a teacher, you will be rewarded with a free Pro account.
That will give you access to PDF files (potentially very useful in class) and all-steps display of projects (also useful if showing projects on-screen in class).
Step 2: Resources
Most teachers new to the site use it first as a resource - either as inspiration for other projects, or for specific instructions to follow.
As well as searching individual projects, there are a growing number of Guides on the site, which collect together the best projects on a particular theme, or projects which go well together, such as the Guide to Kitchen Chemistry or Pre-school Projects.
As a pro member, teachers can access and print off PDF files of projects they like, or they can look at projects in the "all steps" format. This means you can open up an Instructable on-screen in your class (on your interactive whiteboard or projected screen), and scroll through the whole project without having to wait for each step to load up.
It is also useful to copy images into a PowerPoint slideshow, add brief annotations and leave the slideshow cycling non-stop on your screen, to remind you pupils of the main instructions of their task.