I wish I could tell you that I never made any of these mistakes, but that just isn’t true.  A couple of these items have cost me dearly, and honestly, the first one I have learned not once, but twice.

If you’re starting out, this list can save you a lot of trouble in the future.  If you’re an experienced blogger, you may find some pain down there:

• Own your domain – I’ve had lots of calls looking for help to move people off Blogger.com, Typepad.com and other blogging sites.  If you’re going to blog, invest in your own domain so you don’t have do deal with the agony of moving from joesblog.blogspot.com to www.joesblog.com and suffer the inevitable drop in traffic that will come when you move.  I know this one all too well.  I  blogged at Vario.com and when I stopped working with them, had to rebuild my readership here. Not a lot of fun for someone with an ego like mine, let me assure you.  You could also ask http://fakesteve.blogspot.com/ as we found we couldn’t get his traffic moved from that site to his own domain.
• A corollary to this is letting your domain expire.  If it does you only have a short time to get it back before a squatter grabs it or it is gobbled up by a domain reseller.  Used domains are big money…
• Hosted vs. Self-Hosted System – I really love the freedom of having direct access to my own installation of WordPress.  The problem is many non-technical users don’t bother to keep their installations up to date.  My advice is that you go with a hosted service (and I recommend WordPress.com) for your site if you aren’t up to maintaining yourself.  You may find you can’t add all the plugins you might like, but it’ll be virtually impossible for you to completely hose your site. Alternately, you need to get setup with someone experienced who can manage the technical end of your site.  Software updates, theme modifications, plugin setup etc. are the types of things you’ll want.  Be sure to check that the person has a list of sites where they have done similar work using the same system.
• The Snarkfest – At some point we all seem to channel Anthony Bourdain.  Let’s face it, we’re all critics at heart.  The thing is, just because we have an opinion one way or the other, doesn’t mean we’ve got a right to  question someone else’s right to exist.  Remember that your opinion is just that.  Everyone’s got one, so before you shoot your mouth off and take someone to task, have some actual facts to back you up. This isn’t just a blog phenomena – it happens on Twitter even more.  A couple weeks ago I made a snarky comment about Drupal developers. The comment was made with a cocktail in hand, and was a reflection of my dislike for the Drupal system, but I quite unfairly disparaged Drupal developers.  I really wish I could take it back, and I am thankful that Jim Spencer called me on it.
• Plugin-orama – At some point, all WordPress users will discover the WordPress Plugin Directory.  It’s a great repository of all kinds of wonderful functionality, most of which you have no earthly reason to add to your blog.  I’ve seen way to many blogs completely hobbled by incompatible plugins that have changed the functionality of the site so much that it has become unusable. The thing to understand is that plugins are just like the people who write them, fallible.  Many are out of date, some are not coded well to begin with and there are a few that are downright security issues.  Think twice before you introduce a new plugin to your blog.Similarly, many bloggers end up on the “Theme of the Week” club.  Find a good theme and stick with it.  The look is part of your personal brand, so try not to change it too often.  Personally, I find the simpler the better.
• More Ads Than a Stock Car – At some point, we all think how nice it’d be to actually get paid for blogging.  Ads are a great way to earn money, and they are also an excellent way to send readers running for the hills.   David Churbuck calls it “NASCARed” with tons of little ad impressions running on your site, creating one huge and ugly impression on the reader.