It has been written many times that learning anything complicated means eventually realising how many of the underlying details are a relative of something simple. 

In his post “Big Beliefs,” author Morgan Housel references the book “Succeeding” by John Reed which states:

“When you first start to study a field, it seems like you have to memorise a zillion things. You don’t. What you need is to identify the core principles - generally three to twelve of them - that govern the field. The million things you thought you had to memorise are simply vicarious combinations of the core principles.”

The general principles of Teeline shorthand might be described as:

1. Removing unneeded letters from words. Around 40% of the characters in regular handwriting are unnecessary.
2. Getting rid of extra movements when forming handwritten characters.
3. The blending of characters (refer to Beginners Lessons 3, 5, 7, 8, 9, 10, 11, 13, 14, 15 and 17).
4. Using common “contractions” such as special outlines (refer to Beginners Lesson Four), distinguishing outlines (Beginners Lesson Three), and/or word groupings to reduce the number of movements when forming characters. 
5. Using contracted forms for numbers and fractions.

The remainder is just various combinations of the above.