What Makes a Successful Blog?

I'm trying hard to make my blog a successful tool in my writing career.  Over the past few months as I slowly came to the decision to drop my website and go blog only, I did a lot of reading about what makes a blog successful and I thought I'd share what I've compliled.  I'm not claiming all this is factual and not even if I agree with it all. 
One thing everyone seems to agree upon is posting frequently.  It doesn't have to be everyday as that would cut into one's vital writing hours.  But three or more times a week is strongely advised.  I've been trying to do that. 
When should you post? Many experienced bloggers have statistics to prove there is less traffic to their blogs on weekends.  Some can name a specific day they have the most visits and comments.  I'm not sure if this means people do a lot of blog reading at work or not.  I can't read blogs at work but I'm sure many can or they can follow them on their mobile devices. 
Don't make your blogs too long.  Most advise something between 250-1000 words.  Remember your blog isn't about writing a novel.  Have short paragraphs.
Make sure people can comment on your blog and follow their blogs and comment on them.  Don't always be snarky or sarcastic in your posts or comments.  Sometimes is okay but if you do it all the time you'll eventually offend some people.  And learn how to put some of those blogs you follow in your sidebar.  I do this and I'm always adding more and switching them in and out.
People will visit your blog more often if it isn't always about you.  You don't have to be an expert on everything to be able to share your experiences and opinions (like I'm doing here).  But consider who your target is as you decide on the subjects of your posts.  People don't come to my blog expecting to read political rants. 
Keeping a notebook with you always will help you collect ideas for blogs.  I pick up little journals for a dollar a piece at the craft store and jot down anything I might be able to use.  Some pages have only a title with no outline under it, other pages are filled with full outlines where I've collected information from many sources.  This post is right off one of those outlines.
One blogger advised the use of photos where they could be fit in as they add interest and catch a quick-clicker's eye.  Make sure they're qualitiy photos and permitted to be used.
And finally, take the long view.  Be patient and let your following grow.  I started concentrating on building my blog about two months ago.  Before that I was posting less than once per week.  Since the beginning of November, I've doubled my number of followers and make some great connections to other bloggers and readers.  I hope to double that number again over the next few months. 
What advice above don't you agree with?  What would you add?