There is no big secret to this. I find a story someone wrote, I read it, I like it, I write the person and say, "Hi, I'm Darqstar, can I archive your story?"
At that point the person has the option of saying, "Yes, you may." or "No, you can't." If they say no, I figure they must have their reasons and they don't hear from me ever again, at least about that particular story.
If they say yes, then I archive the story. I will do the HTML work (unless they offer to do it. I'd I never refuse!) I will write the teaser. (Again, if you want to write the teaser, that's fine too. People usually write better teasers for their stuff than I do) Basically, all the person has to do is to check my page every once in awhile to make sure I have the latest sections, or send the latest sections directly to me.
The biggest thing to make sure I know is what name you want your story listed under. Usually people will list in the body of the letter what name they are writing this story under, but sometimes they forget and all I have listed is an e-mail name. I'll be more than happy to list a story under your e-mail name, but most people have a real name or an internet name they would prefer to go by.
Where do I find stories to ask people if I can archive?
There are basically three sources. 1: Untold-L 2: The newsgroup alt.comics.fanfiction (which will be refered to from here as ACFF) or 3: Other archives.
Untold L
Untold-L is the place I am most likely to find stories that I want to archive. It's a very dependable mailing list. I would say that 99% of the stories where I've invited the person to be on this archive are from Untold-L. Also, because it is a mailing list, it makes it easy to get future instalments. (Although I do appreciate it when the writer sends a copy directly to my box)
ACFF
Getting stories from this newsgroup is a bit trickier and therefore, less likely to happen. First of all, my news server is iffy. I don't get anywhere from 1/2 to 2/3 of the posts that go there. That makes it hard to know what is there and what isn't.
If I should happen to find your story on ACFF and ask you if I can archive it, don't be surprised if I also ask you if you would mind sending me future sections (if it is a multi-part story) by e-mail. This is to make sure I get them.
Other Archives
I have been known to go to other archives and if I like a story I find on them, then write the writer of the story and ask if I can archive it. However, I don't do this very often, mostly because time is at a premium. Also, I don't like the idea of taking too many stories that are already on a bunch of other archives. Don't get me wrong, I have many stories on Shifting Sands that are on more than one archive, and I don't see anything really wrong with it, I just would rather try to find stories that aren't everywhere else.
I am more likely to look at other archives if it is a slow time. (Not much stuff being submitted to me, or not much stuff on Untold-L)
Well, that is pretty much it for invitations. I'll be honest, I don't do nearly the invitations I used to. It's not that I don't want to, it's just that lately I've been getting a lot more submissions. So please don't be offended if I don't find your stuff and ask you. It doesn't mean that didn't like it, it simply means that I most likely didn't have the time to read your story. If you still want to have your story on this site, you'll have to check out the submission guidelines to see if that might be something you'd like to do.