Just 10 things!

To understand a subject do I do not need to learn everything in it? Is it not good enough if I understand say just the most important 10 things abt it very well. Applying Pareto principle here 80% of the knowledge can be gained with understanding of 20% of the most important aspects.

So when I embark on any new area of learning list down the 10 things that I would seek to learn and understand.