Creating original content is not possible at all times. What a blogger must do when runs of out of original ideas for his new post? At this point he can write something which is not necessary original but of his own. As a blogger you are perfectly entitled to take idea of others and add your won perspective/views to it.
As more and more people are using online tools to find information, it is imperative that your blog provides useful information to the readers. If your blog doesn’t provide useful information, visitors may quickly leave your blog to find the same piece of information somewhere else. Your blog should be providing all the relevant content at a single place so that your readers do not have to blog hop in order to find the same somewhere else.
Look for some of the popular posts on twitter, Facebook and other social media. Once you have found the posts which are popular, see if you could extend the ideas expressed in these posts or add a piece of idea/ advice to improve its usability. Also, publish these posts on your blog providing a link to the original post. In this way you can avoid plagiarism and duplicate content penalty as well. Also, you would provide your readers with information which they require as these posts are already popular among them.