Rule based typesetting like LaTeX (or CSS for the matter) uses lots and lots of lengths that can be adjusted (or adjust itself in relation to some other quantity like the font size or other length). I believe there are over ten regulating how a list is typeset alone. If you typeset for a while you'll pick up a few over time, I'd say parindent and parskip usually come first, some are so obscure you'll never need them, some shouldn't even be touched, since you risk screwing your layout in ways that you thought only MS Word is capable of.
For the middle category of the ones you don't know and still want to adjust I just found a great package. The layouts package enables you to actually see how they all play together for most major latex features. This is so insanely helpful and you don't actually need the package sice everything is reprinted in the manual of course. To see how great it really is see this picture for lists.