i think there is a lot less "method to my madness" since i discovered ebooks, since i now have literally hundreds to choose from at any time, and i'm not too sure myself how to choose the next one sometimes...
in general, if i discover a new author i really like, i tend to get hooked and want to read as much by the same author as i can get my hands on. now i try to read series in order, but since before i got a lot of books from the library, i often had to take whatever i could find even if it wasn't the correct order. also i often find myself reading by theme ; for instance, several years ago i discovered by accident a portugese author i like very much, and then by accident another portugese author i also liked very much, and then for several months i was reading only portugese litterature. or, maybe i'm in the mood to read mysteries, and i'll read quite a lot of mysteries in a row even if they are not all the same author.
lately, i try to keep a balance between reading books i've "planned" to read next because something about them caught my eye, and reading things i've stumbled on accidentally, but then of course i usually revert to my typical theme / author / series behavior... like, i just discovered émile gaboriau on feedbooks, i started with a very short book ("le petit vieux de batignolles") and i liked it so much i immediately started another (much longer) book by him, "monsieur lecoq", and i've got all his books lined up on my liseuse waiting. but maybe after i finish lecoq i'll try to read a different book which has been on my list. and if i don't have something in mind, i just take a look through the books i've got loaded until something catches my eye, and try it out ; sometimes i read a few pages and decide i'm not in the mood for that, so it's lather rinse repeat maybe several times before i really get going.
this is probably not helping you at all is it ?
well, if you come up with a good system, i'd be interested myself...