It's not so much you going down, it's someone else coming up. Search results are not like the Self-Esteem Olympics -- everybody can't come first. Quality content will usually win out over the long run (although the "black hats" occasionally find a temporary loophole that pushes everyone else down for a short time). It's nothing to worry about, really, unless you're showing up on page 32 of the results for your own company name or for a product you've created. If you're in competition with others offering the same or nearly the same information (tech tips, news, opinion, unofficial fan sites) then every once in a while somebody's going to beat you at that game. The more players there are at your table, the harder it is to win the game every time.
Keep creating the best content you can. Make sure it's well-written. Revise old entries if you can make them better. Make your users happy -- they're your best advertisers and your best source of links, and they're not going to spend a lot of time linking to you if your content isn't worth the bother, or if things are hard to find and use. If you are at all serious, then do usability testing. You don't need to be a multinational corporation to do user testing; surely there must be at least a couple of friends or relatives who are not "expert users" and another couple who are. That's really all you need for usability tests. Have people honestly review your content, and listen to your reviewers. When your content goes live, let your users give feedback -- it doesn't need to be public, and you don't need to turn your site into a sort of wiki, but if you have a bunch of volunteers who are willing to help you make your site better, you'd be crazy not to exploit them.