I seem to be the only one to organise games like I do: by title length. You see, all my games are Nintendo ones (I have about 30), and they're Wii U/3DS/Wii/DS, which are all very uniform in terms of titles; i.e. all are centered in the middle of the side, with the same font and colour etc...
So I organise them first by system, and then by title length (So New Super Mario Bros U + Super Luigi U (my longest title) goes on the far left, and Pikmin 4 on the far right, with a nice, clean increasing level of blue background the further right you go, as less space is occupied by the title.
This has the awesome unintended consequence of all my Zelda games being grouped together (by system of course), because the first "row" on the case is always The Legend of Zelda, and the subtitle goes on the second row.
Also, the Nintendo logo is at the bottom of the side of all my games, so that looks nice and consistent as well. All my Wii U games are blue, as in Europe we don't get other coloured ones very often (example; Mario Kart 8 is not red, but blue). The only exception I can think of is Super Mario Maker, but I play that so much it's not ever put on the shelf.
Quite complicated really, but it looks awesome, I must say. I happen to be at the point in time where my total DS/3DS games completely fill a shelf exactly with no space remaining, and my wii/wii U games do the same to another shelf. I'm almost scared of getting Pokemon Moon when it releases, as it'll disturb my coincidental equilibrium! xD