I'm still really quite green at CAD; I've come to it late in life and I only make relatively simple things, perhaps; only simple mechanisms.
But when I look at people getting stuck and asking for help in CAD groups it so often comes down to the knock-on effects of very early mistakes, like squandering the benefits of the base planes by choosing the wrong initial orientation, muddling through with primitives when an extrusion of a sketch would do the job, or making a series of complex circular pockets when a single revolve could have done it better.
Basic familiarity with a few principles and their expression in CAD, and a little study of existing objects gets you a long way.
It interests me that programmers are willing to learn the expressive nuances of individual languages or libraries or methodologies, but as soon as it comes to GUI CAD they dismiss the whole thing as too hard or too obscure. The excitement around LLM text-to-CAD seems emblematic of this; as if the wrong conclusions about GUI interfaces have been drawn from bad experiences of dev GUIs.