For me, knowing Maxwell's Right-Hand Rule doesn't help much. It may seem superficially simple because there are only two possible answers. It's hard because there are so many binary elements that can potentially be flipped:

• Wire coiled clockwise or anti-clockwise?
• Clockwise when looking from above, or clockwise when looking from below?
• Current flowing top to bottom or bottom to top?
• Are we talking conventional current flow (ie, positive to negative) or actual electron flow (the opposite)?
• Is the north end the end that seeks north, or the end which has the same polarity as the north pole?
• Left or right-handed screw (or hand, in some accounts)? (Maxwell has both kinds of rule, one for generators and one for motors.)
• Whether the needle picks up the same polarity as the coil, or the opposite polarity?

Knowing a bit more about the subject arguably makes it harder to remember. The difficulty is forgetting the possible accounts/diagrams which are wrong. I think I now know the answer, but I'll probably have forgotten it within a week, because it is all just too arbitrary to keep in my mind. (And further elucidation probably won't help and isn't requested.)

Of those three figures, I think (1) is correct and (3) is wrong. (In (2) I find it hard to tell whether the coil is clockwise or anti-clockwise.) It's interesting that he started with some correct physics and then got it wrong in the construction. It shows how hard it can be to keep track.

A maxim about 3D rendering programs seems relevant here: all correct renderers contain an even number of polarity errors.