Having Formatting Problems - Here's some easy fixes!
If you've been having formatting problems on LJ like I have, here's some fixes that might help:
Smooshing - If you're editing a post and all your text comes up in one big block, the easiest thing to do is just highlight and copy a copy of your original post (its a good idea to open two windows, one with the original post, and one with the text editor, once you save the text editor you lose the original if you don't have it open in another window as a safety) paste the copy into the text editor. If you have links in the original post, be sure to paste it in the Rich Text side of the editor to preserve the links. Check the preview and test the links before you save anything. (Pasting it into the Rich Text side should also preserve the formatting for italics, bold, and underline, if you copied from the original LJ post.)
Extra Wide Line Breaks - Once you save your post you will probably get extra wide line breaks in the result. That's okay, just hit the edit button and resave it. Resaving seems to reset the regular line breaks. If it doesn't work the first time, just hit edit and resave it again.
Tweaking - You may still need to do some tweaking, such as putting LJ cuts back in, or respacing any odd places, such as if you have a block of text set apart from the regular text, like a quote, but this is a lot less tiresome than having to put in a whole page of line spacing manually.
Auto Formatting - The biggest tip, is to turn off the "auto formatting" checkbox on the html side. Even if you're using the Rich Text side, it seems to help if you uncheck this box.
Remember, when cutting and pasting a post back in itself, keep a spare window with the original open, in case of emergencies. Don't close that window or refresh it until you're satisfied with the replacement post, otherwise you lose your original.
You can paste regular text in the html side, or just type in it, but remember not to paste in that side if you're pasting links, you'll lose them. Only paste links in that side if you have the html for them typed out. However, if you're posting a large text document (or a document from outside LJ) and the line spacing keeps being too wide when you resave it, try pasting that text in the html side. You will lose the links and the italics, bold, and underline, but it should respace the line spacing properly. It takes less time to go back and put back in the italics than to put back in all the blank lines.
I hope this helps everyone.