You wake up in the night with a fantastic idea on how to improve LiveJournal. Great! But who should you tell about your idea?
Your first stop should be to check that someone else hasn't suggested your idea before. You can do this by reading the memories section (http://www.livejournal.com/tools/memories.bml?user=suggestions) of the suggestions community (http://www.livejournal.com/userinfo.bml?user=suggestions).
After checking that your idea hasn't already been posted about, read through the guidelines at http://www.livejournal.com/suggestions/, and submit it!
Members of the community will discuss your idea and possibly make further suggestions or improvements. Within a month, presuming your idea is feasible, the maintainers of the suggestions community will make a poll where other LiveJournal members can vote on your idea. Not all suggestions will necessarily be voted on, and not all those with a favourable vote will necessarily be implemented. If your suggestion gains approval, it will be submitted to LiveJournal's project tracking system, where it will sit for weeks gathering dust.
Not entirely how I imagine it will end up, but if we don't get something up to pick apart, like many suggestions, nothing will happen. ;)