so, maybe this guide isn't really all that necessary, but i struggled to get a couple of the endings. and i have lots of spare time, so i went through the game again and wrote down my dialog paths for each ending. so, here you go. also, there might be different ways to get the endings, i know there are plenty for the georgia ending. oh, and there might be spoilers, i guess. keeping this pretty basic, but yeah. maybe you will percieve these as spoilers, maybe you won't. whatever, read on if you want.

UPDATE: (this update is invalidated by the next update, but i feel too lazy to delete it, so it stays)
as of nov. 2, 2015, achievements have been added. with my guide, you'll get seven of the eight, still working on getting the last one (Constancy to an Ideal Object). check each ending section to see what achievements you'll get with that path.
Additional note: a couple of the achievements might be obtained in other ways, this is just how i happened to get them.

another UPDATE:
12/3/2015
got the last achievement (Constancy to an Ideal Object) added to the guide and to my account. guide should be pretty much complete now. or at least i call it complete. maybe you won't. but i won't judge you if you think that way.

you get this one just a little into the beginning of the game, before any choices are made.

note: if you've played before achievements were added to the game, this one might not unlock for you. check the in the comments for the one by @ebihime to find out how to fix that. (many thanks ebihime)

This'll get you the first four pictures in the CG gallery. this is what i refer to as the "Lillian Ending"
so choose these to get it:

ignore her
say nothing
I thought you were ignoring me
defend lillian
agree with Lillian
Confide in her

achievements: fear in solitude, prelude, to lillian wordsmith

ending 2 gets you the next CG in the gallery. De Quincey ending
choose:

approach her
say nothing
it's nothing, really
say nothing
berate her
change the subject
tell a lie
De quincey

achievements: confessions of an english opium eater

this will get you three pics in the CG gallery, i think. i call it "Roberta Ending". my personal favorite, if you were wondering. (no, you weren't wondering, why am i pretending you were...?) yeah, moving on.
choose:

just ignore her
apologize to roberta
it's nothing
say nothing
berate lillian
confide in lillian
tell her
roberta

achievements: goldilocks & 3 bears, pains of sleep

probably the easiest to get. i got this one my first three playthroughs, trying different things each time, but this is my latest attempt. this will get you the last CG.
choose:

approach her
say nothing
it's nothing
defend her
agree with her
confide in lillian
tell a lie
georgia and percy

achievements: suicides argument

I found this to be a pretty cool game. well written, great art style. really captured the mood the creators were trying for perfectly.

so, if you find a flaw in my guide or some super secret ending that i missed, let me know and i'll eventually get it fixed (no, i won't capitalize anything that isn't capitalized, i'm too lazy for that right now.) and i will give credit where credit is due.

yeah, thanks for reading my guide, hope it helped. if not, feel free to leave a nasty comment and have the satisfaction that you might have made me cry. (no, not really, but feel free to think that if it makes you feel better.)

also, my thanks to the people who made this game, i really enjoyed playing and hope that you'll make more great games in the future. i mean, i'll probably have money to spend on them if you do make more. and money is always cool, even if it isn't what you are in this for. but yeah, thanks.