Single herbs in the Chinese materia medica are the building blocks upon which formulas are built. Learning them in the TCM world just takes brutal, rote memorization and repetition. You need to know:
Depending on your school, you might need to know the Pinyin name, the Latin pharmaceutical name, the English name, or a combination of these.
The internal action of the herb as far as how it affects the interior climate of the body.
This is sometimes called the five flavors, but there are actually more than that. Each flavor has an action and therefore an effect on the body.
Where it goes in the body.
Each herb is associated with one or more channels in the body. If you want to affect what happens in the meridians/channels, you need to know where that herb will travel most effectively.
What herbs play well together and which ones don’t.
Below are my links to my class notes from my Single Herbs days, may I never have to repeat them! How herbs are categorized can vary from school to school, author to author. Most of us have very similar categories. Bear in mind if your school does it differently, that doesn’t mean it’s wrong!
Release exterior, clear heat, drain downward, and drain damp
Dispel wind/damp, resolve phlegm, aromatic that transform damp, food stagnation, regulate qi, regulate blood, warm exterior/expel cold
Tonification herbs (Qi tonifying, Blood tonifying, Yang tonifying, Yin tonifying), stabilize and bind herbs (stabilize exterior, stabilize Lung and Intestines, stabilize Kidney), calm Shen/spirit herbs, subdue Liver yang, extinguish Liver wind/stop tremors, aromatics to open orificies, parasite expelling herbs, herbs for external application