/ic/ - Artwork/Critique

Learning through my lessons/fundamentals and I'm mostly practicing them right now.

I need a clarification on the "upside down" drawing that works on curing your symbol drawing.
I looked at a bunch of books and videos of observational drawing and they put that into practice, but what about the 3d forms the subject has? What I'm specifically asking is: what kind of mindset/questions should I ask when doing these? I feel like whenever I do these, I just think about how to make each line accurate instead of knowing which collection of lines represents what. fuck I don't know how to explain it properly but I'm sure that I'm doing it wrong.
I know that drawing accurate lines is important so that when you do studies, you can accurately draw your 3d forms (for example, drawing a cube in a specific angle that represents the main 'body' of a box-like object) and the rest of the details won't fall over.
Whenever I'm doing the upside down exercises, I feel like I'm drawing focusing on the small details too much instead of the large forms. The black/white contrasted images will be broken down into 2D shapes too and its making it harder for me to think in 3d.
What do I do/how do I shift my brain into the accurate general forms first instead of small detail.

Sorry if I'm speaking gibberish because I don't know how to explain my problem + I'm tired because of wage slavery.