I often find it confusing when to actually use commas, (i) and when not to. As a result, to prevent run-on or long sentences, I tend to put them in where I would pause in speech. Usually, this does not pose that many problems anymore, but in somewhat more complicated situations (ii) I still find myself wondering if the pause in speech would generate a comma in writing (iii) or not.
I know there are many questions about punctuation of this sort, but all I've found have been too specific to put me at ease. As a concrete example, I am struggling with the following sentence from my thesis:
(1) Dynamical properties usually mean properties of a system that are unchanged as the system progresses. For instance, this incorporates the properties of being fix, periodic, and stable, for points, but also as we shall see, for orbits.
Question 1: In (1), I do not really know how to use commas in the second sentence. Is the problem punctuation or rather formulation? Should I restate the whole sentence, or could commas be moved/removed to make it better? Initially, I even had a comma after 'also'; I am not really sure about this either. (To make things clear: 'fix', 'periodic', and 'stable' are words describing properties of the noun 'point', but also of 'orbits'.)
Question 2 (optional): Consider (i), (ii), and (iii) in §1 of this question. In (i), is the comma correct/wrong or perhaps correct but unnecessary? (Does it perhaps have to be 'and when not to use commas.', for it to have a comma?). In (ii), the sentence becomes very long, and I find my self wanting to insert a comma, but I feel it is wrong here, am I correct? In (iii) I am pretty sure there should be no comma, but exactly why is this? (Is it just to short?)
English is not my first language, but feel free to nitpick on as much grammar as you want throughout. I am eager to learn as much as I can.