This is one of the most difficult and common problem for bloggers, to select and suggest a unique and quality post for there blogs, and write about that post. Due to increase in blogging, it is very difficult to write on unique topics. Because You may be thinking of any topic to write, but someone has already written about that topic. This will force you to write on the same topic, but in your own words. This is also called quality and uniqueness.
Writing in your own words can decrease duplicate content issue, and you can get high SERP for your article in search engines. Always keep quality in your post, because the better the quality, the better will be ranking. It is better to write one quality article, instead of 10 copy pasted articles. Just think about the topic and elaborate the main idea first and then start writing on its features, advantages, disadvantages etc.
Join all popular Social Media website and visit on regularly basis. Social Media is the only way to get latest news and stuffs. You can then write a Post about that news.
Post in forums, and try to know about common problem faced by bloggers, and then address the problems in your blog.
Always search google for a topic, you are thinking about to write. This will help you to know what others are talking about that topic.
Keep your post short and descriptive, so that visitors can easily get there points.
You can also write this post to get more clear idea about how to write a quality post for your blog.