I am new to the hand tool world. After finally figuring out how to get my hand planes sharp (due in large part to some advice I received here), I am trying to learn how to square and dimension boards by hand. I have watched a ton of videos on the process on YouTube, and I have also done a lot of reading on the subject. My attempts so far have generally followed the approach advocated by Mike Siemsen (https://www.youtube.com/watch?v=oEdgF8NDsB0).
My results so far have been very mixed, and I really struggle with getting the face flat. I also seem to waste a large amount of wood during the milling process. My primary issue is that after I get a board reasonably flat, when I reference the board to my table saw top, I can never completely eliminate all rocking. Is this to be expected? Will there always be some deviations that can be detected by tapping the board corners when the board is referenced against something that has been machined flat like a granite slab or a table saw?
Also, regarding the "tap test" for board flatness, are there any good references for how to use the tapping to identify the next steps in the milling process? In every video I watch, the instructor seems to be able to magically know how to interpret certain types of rocking to identify what to do with the board next. My interpretation of the rocking patterns seems to frequently make things worse rather than better, and I feel like I am really missing something here.
Lastly, any suggestions for how to improve hand milling by hand? Right now I am just practicing by working through a scrap pile. The shavings-to-final-board ratio is not favorable.