Steps to LJ stardom:
1>It helps to be a member, since you can create and edit a style for your journal. It allows you to have much cooler journal designs than you can do with the default style. More info on how to do this is available at http://www.livejournal.com/support/. don't hesitate to visit the support page... if the answer isn't in the FAQ on the support page, your fellow LJ users are kind enough to spend the time to help you out.
2> Start looking around more and finding other people with similar interests. Use the Find Users features! Read other user's journals and don't be afraid to post a comment to their entries. Add them to your friends list, even! (No, you don't need to ask permission first, though it is often nice to send the person a little note saying you just added them...) That way, you can click on your friends link and read what they are up to, and they will probably notice you're out there and add you to their friends list. It also helps to take a look at their friends list, too... often, you will find some pretty cool people that way that you might never have noticed otherwise.
3> Explore the community. Check out the community page and check out all the links. View all the communities that we have on LiveJournal. Communities are like journals that multiple people can post to. There are communities on tons of different interests... Not bad, since we just created communities about a month ago.
4> List lots of interests and have consistent names. The more interests you have, the more people you will have similar interests with, and the more people will notice your journal. Also, make sure that you list interest names that are consistent with other people's names. For instance, if you list "camping trips" as an interest, only one other person has that interest listed... but if you list "camping", 539 users list camping as an interest. They might notice you if you also have camping as an interest...
5> Participate! Don't just sit there... start something. Share your interests and your passions with others. There's directions on the community page on how to make a community. You can also participate by trying to answer user questions in the Support Area... or if you have ideas on how LiveJournal could be better or you'd like to help LiveJournal, drop by the LiveJournal Business Community... we coordinate all sorts of activities there and we're always looking for more people who have ideas or would like to help us out. You'd be amazed how quickly you can get get noticed...!
Of course, the two most important things that matter for the success of any journal is whether you take an interest in those around you and whether you have something to say about your life that resonates with others. Is popularity really important?! Not really... but there's no denying the value of good friends and kindred spirits.
They're out there. All you have to do to start things off is to say hello...