Name refactor - rename an entity (variable, function/method, class) for clarity in order to reduce logical tension
Extract variable - if a sequence of logic starts repeating itself it's time to create an entity from the snippet
Extract method/function
Extract class - inheritance
Extract module - when you begin to see a recurring theme around a group of entities then it's time to isolate them into their own module
Extract package - same but applies to a collection of modules that harmoniously work together
Inline - getting rid of unnecessary variables