A method is a specific set of steps that can be performed in order to achieve a desired outcome. For example: "If you want the violin to sound louder, pull the bow faster, and put more weight on the strings"; "If you are about to be kicked in the face, pull your arm up and block". As usual, such rules are most effective when they are non-verbal and automatically applied, rather than thought about beforehand. Unfortunately, thinking as much as Sherlock Holmes does when he fights distracts rather than focuses effort and attention.
In an abstract sense, whereas we normally tend to consider declarative knowledge as a sort of "web" of associations, procedural methods are more like algorithms or enumerations - "if this, do that". Of course, since there are usually many ways to achieve the same outcome, you could easily end up confused by a thought-process sounding something like: "If this, do that... or that ... or that ... or...". Back in one of my first posts (Procedural Knowledge) I said that "a procedural knowledge item is characterised by the purpose the procedure serves... if you know two ways of achieving exactly the same thing then one of those ways is redundant (once again, redundancy is not necessarily bad)"
In contrast, a principle refers to a basic criterion which must be met by any specific method. For example, when playing the violin (or most musical instruments) it is important to keep as relaxed as possible, even in a performance, so that 1) you don't get sore muscles or RSI from playing, and 2) the music does not get affected (eg scratchy, squeaky or otherwise distasteful sounds). In order to relax this way, some people use the Alexander Method, some meditate beforehand, and some just breathe deep. Each of these is a different method, but they all serve the same principle - to relax in order to play better music.
In general, principles are declarative concepts and must be understood sooner or later. But when it is time to build up skill, methods are the way to go. Furthermore, it doesn't matter which method you use, as long as it works.
An action item is a "micro-skill" (rather than a skill, per se), which is used to achieve a small, specific effect during application of a more advanced skill. In a way, these are like the "minimum information" elements you would be used to from SuperMemo.
- a martial artist can learn a simple kick, and then combine it with many other actions for different purposes or effects
- an artist can learn how to draw simple shapes such as oval, circles and squares, and then use these micro-skills when drawing much more advanced drawings
- a violinist can first learn staccato bowing on the C major scale (for example), before integrating this bowing technique into endless numbers of real pieces
- Any musical piece, or any piece of artwork, consists of many individual steps taken that make an impression on the onlooker through their overall, combined effect
- A soccer player often makes use of his running, tackling, dribbling (and acting) skills in a game, even while practicing each in isolation during practice sessions
- A computer programmer writes a fully functional piece of software, using many small tricks and methods accumulated over many hundreds of hours