After starting a number of blogs and watching most auger in with flames, I have learned the hard way a few tips that have elevated me to blogging mediocrity.  While I am sure most of these hints have been covered, there may be a few that are helpful.

Regular posts: If you write something that people, not web crawlers, like, you need to keep them happy.  One post a week minimum, with two being a better choice.  Daily bloggers are fantastic, it's often not an option for the lone blogger.  Companies with blogs should have enough contributors to keep things current (like here at SEOmoz).

Set realistic goals: If you are just blogging for AdSense cash or affiliate earnings, you need to know you have a long row to hoe.  Yes, you can still hit a home run, but the competition increases every day.  Unless you happen to be tight with Britney, Paris, or Lindsey, odds are it will take time for you to find your niche.  That said, there are plenty of niches that can be filled.

Content, Content, Content: Chose a theme that really blows wind up your skirt!  You need to write lots of relevant content, and if you are not a professional writer it will be hard to keep the content coming.  For the average blogger, write about what is a passion in your life.  If you are jaded, write about the things that tick you off.  Give your readers part of yourself.  Being a gifted writer helps, but clear, simple writing styles work extremely well.  Say what you think with good spelling and consistent grammar.  You don't have to have great grammar, you just have to convey thoughts without people cringing.

Promotion? Not at first.  Search engines will find your stuff.  Use that time to build content, review/edit your content, and plan more content.  When the time for promotion hits, promote only the best of your content. Start slowly in topic-related forums to get feedback.  With good feedback, more involvement in related forums will increase your traffic and generate inbound links. 

Links: Link tricks are best left to guys with high ranked sites to play with.  The average blogger should build links the old fashioned way, with signatures in popular topic related forums.  You can also get cheap links by mentioning towns or searched topics.  Topix.com searches the web for news related to just about every town in the US and tons of topics.  There are plenty of other sites that auto include links to related content.  Write more content and you will have more relevant inbound links.  The better your topic selection and writing skills, the more unsolicited links you will get.

Keyword suggestion tools:  Wordtracker, Google Sandbox, and Keyword Discovery (and, with any luck, SEOmoz, hint hint [from Rebecca: we read you loud and clear]) have keyword suggestion tools that will help you focus the theme of your blog to improve traffic.  Running your theme or a few topics through the tools will give you better key phrases for your content and ideas for future content.

Keyword density: If you write focused content, the keyword density is automatic.  Your target is 3 to 5 percent of your page URL.  A descriptive title reinforced in the first paragraph with a mention in the body and at the conclusion covers the keyword density issue.  A photo caption with the keywords is gravy.  Using related terms in the text spices it all up.

That is enough for a first post.  Oh, did I mention short pithy paragraphs with meaningful headings?