Hi and welcome! The mechanics of posting are a lot easier (and shorter) to talk about than actual writing help. If you'd like to talk about the writing itself, let me know and we can get into it (probably in e-mail) but for now I'm going to assume you want to know about posting stories to LJ. :)
Things like italics and bolding need to be indicated with HTML code. Use <i> and </i> to indicate italics, and <b> and </b> to indicate bolding. So something like <i>this</i> would turn out looking like this.
Don't use *asterisks* or _underlines_ or whatever -- since the HTML code is available, proper emphasis should be used. *This* sort of thing is what we used in the pre-web days, because all we had was what was on our keyboards.
Even if you know how, don't mess around with the font or colors or sizes when you post a story. The LiveJournal defaults are fine and very readable. Some people post in weird colors like red on black because they think it looks cool and goth, or green on tan because it looks arty or something, or they post in all italic or in five-point microprint (which I'm not even going to reproduce) for who knows what reason, and a lot of readers will take one look, squint, and move on to the next story. If something is at all difficult to read, you will lose readers. If you're posting a story at all then I'll assume you want people to read and enjoy it :) so don't sabotage yourself trying to look cool or different. Let your story speak for itself.
If you're using a full-feature word processor like Word, make sure you turn off all the "helpful" crap like smart quotes and such. Don't use the Format:Paragraph function to put blank spaces in between paragraphs -- you need a hard carriage return to make a blank line after each paragraph, and three blank lines in between scenes. Eliminating those blank lines and letting your story run all together in a huge monoblock will lose you readers.
Fic is generally posted with a header at the top, showing things like the title, author's name, fandom if you're posting to a multi-fandom community, pairing if appropriate, rating, summary, disclaimer, etc. My headers look like this:
<b>Title:</b> Family Obligations, Chapter 6
<b>Fandom:</b> Celebrity RPS
<b>Pairing:</b> Orlando Bloom/Sean Bean
<b>Challenge:</b> AU Orlibean. Sean is hired to kidnap Orlando who he assumes is a spoiled rich kid who turns out to be anything but, when the ransom isn't paid the order comes down for Sean to kill him. It's a race against time to get them both to safety. Written for <lj user="abandt">'s request at <lj user="the_challenger">.
<b>Summary:</b> Sean's little brother has a taste for the ponies but no talent when it comes to choosing winners, and owes a local gangster a lot more money than he can come up with. Sean agrees to do an "easy job" in payment of the debt -- kidnapping a spoiled young punk named Bloom and hanging on to him while the gangster gets a ransom from the lad's family. It should've been a simple job, but then things started to get complicated.
<b>Disclaimer:</b> I don't own anyone you recognize. I know nothing about their social lives or sexual activities, more's the pity. This is fiction, period. It is done as a labor of love and I make no money from it.
This is the header of my current WIP (Work In Progress -- a story I'm writing and posting one chapter at a time.)
I have a "Challenge" line because I'm writing this story at the request of someone else, who posted a prompt or scenario and asked if someone would write a story based on it. I could've put "Prompt" here and it would've meant essentially the same thing. If you're not writing to a challenge or prompt, then just leave this line out.
The summary is important. This is one of the main things people will look at when they decide whether or not to read your story. Give it some thought and pretend you're writing the blurb that goes on the back cover of a paperback book. Some people just say, "Please read and review!" or "I can't think of a summary but it's good I promise!" or something like that -- don't do that. :/ Write a real summary, even if it's sort of short.
The disclaimer is important too. This states explicitly that you're not claiming ownership of the characters, etc. Some people, when they're writing fictional-person fanfic (like something based on Blood Ties) will state specifically in their disclaimer that the characters etc. belong to the writer or studio or whichever (such as, "Henry and Mike belong to Tanya Huff and not me, I'm just playing with them" or something similar) and that's cool, but just saying they're not yours is adequate.
This bit -- <lj user="the_challenger"> -- is a piece of code particular to LJ which lets you refer to someone else's journal (whether it's a personal journal or a community) and automatically create a link to that journal at the same time. So this: <lj user="angiepen"> would turn into this: angiepen. :)
Since I'm writing a multi-chaptered story, I also include links between the chapters. This makes it easier for a reader who wants to start at the beginning and go all the way through, or for someone who doesn't remember what happened in the last chapter and wants to refresh, or for someone who's only just found my story and wants to find the first chapter so they can read the whole thing. LJ lets you put in a link directly to a specific post in any journal, or to any other web page outside of LJ, like this:
<a href="http://www.example.com/">My Homepage</a>
Replace the example URL (everything between the "double quotes") with the URL of the target page -- the place you want the reader to go when they click on the link. Replace the "My Homepage" part with whatever text you want the link to say. So just below the header of my story, there's a block that looks like this:
Previous Chapters: <a href="http://angiepen.livejournal.com/36966.html">One</a>, <a href="http://angiepen.livejournal.com/37250.html">Two</a>, <a href="http://angiepen.livejournal.com/37387.html">Three</a>, <a href="http://angiepen.livejournal.com/37974.html">Four</a>, <a href="http://angiepen.livejournal.com/38766.html">Five</a>
After I post it, it'll look like this:
Previous Chapters: One, Two, Three, Four, Five
and each of the numbers will be a clickable link taking the reader back to that chapter. At the bottom of Chapter Five, after I've posted Chapter Six, I'll add this:
Next Chapter: <a href="http://angiepen.livejournal.com/XXXXX.html">Six</a>
with whatever the post number of Chapter Six is, in place of the "XXXXX" part. This will let someone who's read to the bottom of Chapter Five to just click on that link and get to Chapter Six.
The idea with all this linking is to make it as easy as possible for a reader to read your story. I read a lot of fics and I have a pretty huge Flist. I don't read every story -- I'll skip stories for a variety of reasons -- and if I come across a story that's "Someone's Totally Cool Fic," Chapter 18 and I don't remember whether I'm reading that particular story or not, and the summary doesn't jog my memory and there's no easy link I can use to glance over Chapter 17 and see if it rings any bells, I'll probably shrug and go on to the next story on my Flist. There's a lot of great fic out there and if the writer of one particular fic can't be bothered to make things convenient for me then I probably can't be bothered to read their story.
When I'm ready to post, my preference is to post the actual story into my own journal, then link it to any communities where I want to share it. The main advantage of this is that it's easier to make sure you've caught all the comments on your story and responded to them. Also, putting the fic in your own journal means all or at least most of the comments will also probably end up in your journal, under your control. If the story itself is posted directly to a community and that community ends up getting deleted for whatever reason, any comments posted to it will be deleted as well and that sucks. :P
So the full story goes in my journal, with an LJ cut to prevent it being too long on my friends' Flists. An LJ cut looks like this:
and it "cuts" off the text of your post. Anything above the cut will show on the Flist of anyone who has you friended. Anything underneath the cut will be hidden. The cut generates a link which says "Read more..." and if a reader wants to read more then they can click on the link and they'll see the rest of your post. Most communities require you to use a cut if you're posting more than a few paragraphs, and even in your own journal, you'll usually get some complaints if you don't cut longer posts.
Once your story (or any other post) has been pasted or typed into the edit box, always Preview before you post. You might have to hit the [More Options...] button to get a [Preview] button to show. Previewing lets you look over your story or post one last time, make sure all your HTML is working -- a typo on a closing tag (the ones with a slash in them) can set the entire rest of your post into italics or whatever, which is embarassing -- that your formatting looks good, and give it a last once-over for typos and such. If you make any changes, make sure you copy and paste them into your story file on your hard disk. When it looks good, post.
Next, go to the community where you want to post a link to your story and open up a Post box. Go to the story file on your computer (the one you just updated if you made any changes after looking over the Preview ;) ) and copy everything above the LJ cut. Paste that into the community's Post box. Then skip a line and put in a link:
<a href="http://blaisehellfire.livejournal.com/XXX.html">Your Story Title</a>
Do a Preview, and if it looks good then post.
What will show in the community is your header, then a blank line, then "Your Story Title" as a clickable link which will take readers to your journal so they can read the story.
Note that it's considered bad form to Friendslock a story in your journal and post a link to it in a community. People who read the community, even if they're members, will click on that link and get an error message saying they're not authorized to read your post, unless you have their journal friended. It's like putting a party invitation up on a bulletin board at work and then when people show up, saying, "You're not a friend of mine!" and slamming the door in their face. Rude. :/
I know this is a lot :) but hopefully it all makes sense, a piece at a time. If you have any questions, feel free to holler. [wave]
Angie [angiepen at gmail dot com]