While I don't have anything to offer for the initial point (although I suspect that your second issue may be causing you to feel that the images you find on google don't seem to be enough, when it's just a matter of how you're approaching them), these notes explain the process we employ to observe our reference images and ultimately understand the individual textural forms that they're conveying to us.

Many students, despite those notes, focus only on observational drawing - meaning they look at their reference image, see certain shapes, and attempt to draw those shapes on the page without necessarily considering what they're meant to represent or convey. They skip the "understanding" stage, and thus never have the opportunity to think about how those forms exist in three dimensions.