One thing I know when I'm teaching stitches via computer is you'll be in front of your computer trying to figure out the stitches as we go, and I encourage you to follow along by bringing a doodle cloth, some floss, a needle, and scissors to the computer with you. Then, when I give the steps, you can try them. I always suggest, however, that you not bring magnet boards or magnets anywhere near your computer because they can destroy your hard drive. My point is, if there's anything special about the place you choose to teach that requires something extra, you'll need to supply it. Another consideration you'll want to make before you begin teaching someone to stitch is how long you want the session to be.
Attention spans vary greatly.
Obviously, most children have short attention spans, so you may want more than one session with them, and each one will be shorter than it may be with an adult. If I'm going to teach someone to stitch, I want to make it as pleasant an experience as possible because I'd like that person or those people to learn to love stitching as much as I do. One of the most valuable things you can do, in addition to some of the above ideas, is to give praise and encouragement as you go. Some folks will pick up what you're trying to teach very easily, while others will become frustrated right away. Encouraging them can be the one thing that may keep them stitching.