I suggest you look at Mathoma's videos¹ on the topic on YouTube. His explaining is so simple (even too simple, some would say) that GA becomes a no-brainer. The magic really happens with this teacher (for me). A lot like Khan, for comparison.
As someone who has to teach GA, may I ask what you tried and what you found difficult? I see problems with the non-standard notation, for example. I also think that it is much easier to understand 3D-GA starting with 2D or even 1D, and of course using a non-formal approach (as we do with vectors). It is also hard to find nice examples between the very obvious and very difficult stuff.
I think it is mainly the extra time spent on the foundational definitions - ie. multiple paragraphs and multiple interactive widgets just to clarify what is meant by a bi-vector.
I don’t claim to have delved very deep in the topic before, but of course it is standard to start with definitions - and I found these definitions particularly clear & disambiguated.
