something specific I can learn about in a book or tutorial?
no books there - 'a little practice does a lot of good'
with display problems of your kind, the stylesheet is the first suspect;
(in other cases i would run the html validator http://validator.w3.org/ to check for invalid nested divs)
the rest is experience - over time, i have seen many cases where a mistake in the stylesheet blocks the execution of styles further down - this is not unique to your problem.
i use firefox web developer add-on with its ablity to tweak the styles (and more) in real time in the browser.
then it is down to making a copy of the style that is blocked, and inserting it somewhere higher up into the stylesheet, to see if that brings the formatting back. and working the way down until the style is blocked again - narrowing down the lines of styles until the typing error is found.
at other times i copy the style into dreamweaver with its syntax highlighting, which sometimes indicates the broken line.
or i use the http://jigsaw.w3.org/css-validator/ - again, this sometimes gives an indication of the broken area.