Yes, believe it, or not I am not perfect. With 2009 being my first year of blogging I have made mistakes along the way.
Picking the right Niche
I made this mistake twice in 2009. I made my niche based solely on a game I loved. The problem is I fell out of love twice. Once with my Warhammer blog, and another with my Aion blog. It was the third time that I realized that my niche may have been to small, and a general gaming blog works better. It is much easier to write about multiple games, than just one.
Not using your own Domain name
I made my first two blogs without doing much research on blogging. I just decided to do it. I googled something like blog programs, and the next thing you know I had a Blogspot blog. I didn't put too much time into the whole idea. I ended up with a warhammerblogtimes.blogspot.com, and aiontavern.blogspot.com blog addresses. I didn't know any better.
I now know the importance of your blog having its own domain address, and having a hosting company. The search engines love a real URL compared to a Blogspot, or Wordpress extension. It improves your pagerank tremendously, and SEO optimization. Also the longer you have a domain the better search engines love you.
Not using Twitter to its full marketing power
It wasn't until towards the end of the year I realized how valuable Twitter is. The whole year pretty much passed by before I realized the marketing power of my Twitter account. I now know the importance of my profile, picture, favorites, retweeting, and more.
Monetizing my blog the wrong way
I didn't realize the income potential I was giving away by having Google Adsense ads after each post. I realized the pennies I was making was pretty pointless on impressions, and clicks. It defeated the purpose of keeping visitors on my blog, and making other people rich instead.
Not allowing visitors to comment
I finally just woke up, and activated comments on my blog. I now know the importance of interacting with my visitors, and building relationships. No one enjoys coming to a blog with no social interaction. Visitors also enjoy the interaction with each other on the comments, and it gives them a chance to increase traffic to their blog too.
Having a Blogroll
I love the idea of the blogroll, and giving your fellow bloggers in your niche some link love. The problem I found is it was the biggest exit from my blog. I work hard to keep people on my blog, and not give them an invitation to leave for another blog. I removed my blogroll a few months ago. I have seen my length of visits, pages visited more than double since I did it. It was prime marketing space I could use for my own site instead.
Not being Controversial
I found out pretty quickly that my visitors loved controversy. If I just posted something about a patch announcement, bug fix, or etc my daily visits were small. After the first few months I realized if I made my post say Bright Wizards Scorch Earth is not Overpowered compared to Bright Wizard Scorch Earth Patch Changes it would make a huge difference in visitors, and rage within comments on the posts. Posts need to tuck at peoples emotions.
Misunderstanding using Links within posts
I read somewhere that it was good to have links within your posts. I went a little overboard, and the saddest part is I gave visitors about 10 reasons to leave my blog in every post. I soon realized the marketing power of only linking within my own blog, or affiliate links.