Ultralearning: Drilling

As with so many aspects of more efficient learning, the key is to concentrate on the hard things.  It sounds easier than it is.  When confronted with things that are hard, you have to battle your own fears of not being up to the task (comment mine), and the very natural tendency to avoid hard things.  The mind is slippery.  You have to stay alert and force the mind to concentrate on what's difficult. The distinction in ultralearning is to be extremely mindful and keep it difficult. Don't waste time on what you already know.
Some aspects of drilling.
Divide by time:  Particularly valuable for things like music or pronunciation.  drill the difficult aspect and skip the rest
Divide by cognitive components:  eg  pronunciation versus vocabulary
in, say, geography how countries relate to the whole, what are components within the country
Magnifying glass
This is to do 10 times the intensity on things that are hard for you.  His example was research.  He spent 10 X on researching something because he was having a hard time doing that.
Prerequisites
If you find you're lost and not getting something.  Go backwards until you find the step that you don't understand.