Income. When I was new to IM, I wanted each blog to be profitable. Now I know that most blogs will fail. I am not dependent on this source and do not invest much time, money in it because of this. But still trying with new forums because I enjoy the process.
Word count and keyword density . I used to get really worked up about these untiil recently when I realized they are not more powerful then intent and structure. I do not give a second thought to them anymore, and I just concentrate on making sure that the content is relevant and readable.
I gave up worrying about creating the perfect schedule for article publications and SEO optimization of each and every aspect. The key things that are needed are good content, understianding the needs of people and improving it according to their feedback.
One thing I no longer worry about is if everything needs to be ranked right away. There are articles that will not move at all for many months until suddenly they start gaining momentum as the site becuomes more authoritative on the topic. It has helped me keep many imp articles alive.
I ceased to care about hitting a target word count. An article with around 1,500 words that fails to answer the query is still a poor one, whereas a shorter one with better ideas works fine. Now, my emphasis lies more on the purpose of the search and the usability of the content.