Hi there @Chris!
I agree with @Apomixis that you need to be very careful with “subcomponents” of a character component.
However, in my recent relearning of Chinese (after mostly forgetting it during a neglectful decade or two,) I decided to do it “my” way this time and learn all the tinier components-within-components and thoroughly exploit the mnemonic system Skritter makes possible.
So for my new learning system, every time I created a word list, I created a companion components list for it, and learned them before the word list.
I don’t recommend this system for anyone in normal classroom learning - the pace would really slow down your ability to learn the required list.
And I have certainly since abandoned some of the components that I learned, as they are just too rare to be useful.
But I was willing to slow it down this time in self-teaching in order to learn more thoroughly than classroom learning allows. Doing it “my” way this time has been so helpful and given me a tremendous advantage at what is now a much more advanced level. There isn’t a character anymore whose components I don’t already know, so mnemonics come quickly.
For your example 商, it is true that it doesn’t easily officially break down. However, I found it helpful for mnemonic purposes to read the top part as a partial 立 “stand” and the bottom part is 冏 jiong3 for “bright”
So my mnemonic becomes: “ stand bright in COMMERCE by CONSULTing,” where the bold words are the components and the capitalised words are the meaning.
If you ever need help with components/subcomponents, just message me. I treated myself to most of Pleco’s many dictionaries, so I enjoy more detailed and less common or accessible definitions in many cases.
冏 jiong3 “bright” by the way is 冂 jiong1 for “wide” and 㕣 yan3 for “marsh at the foot of hills” (“eight river mouths make a MARSH”), which, if you’ve ever canoed in a marsh, makes sense as a metaphor for “bright” : “wide marshes” are blazing hot in summer and filled with light, as they are completely treeless.