A first encounter with sketchnoting
One of the talks I attended at the Microsoft Build conference was called "Sketchnoting 101" and given by Nitya Narasimhan. It gave a very high level view of the approach and how anyone can quickly pick it up.
Having seen the rough approach I think I have a preference for trying it electronically as it means I can make corrections and play around with layouts. It seems that the most common tool for this is Procreate however this unfortunately is limited to the Apple ecosystem.
There seems to be a potential opportunity for someone to create an application specifically geared to sketchnoting as it seems to be gaining traction. This would include excellent support for producing text in a sketch style (including easy ways to add emphasis, change style, resize, etc.). In addition it could have a link to a large library of pre-drawn sketches for subject which could include the ubiquitous star people that could easily be tweaked. It could be finished with the paint style colouring that seems to be common and makes it look more hand drawn.
In the meantime, there is a link below to a site that I found contained a pretty good summary of the main techniques used.