I start by looking at different news sources and websites that I generally already look at on a regular basis. Once I have found a topic that I am interested in, generally its the first story that I read until the end without getting distracted and moving on. I take some time to think about the topic. I try to look up any background information or other websites that may be attached to the story. If the story is quoting another story, I try to track down the original. If its talking about a scientific paper I try my best to find it. I also look at any websites of any organizations involved in order to see if they have comented on the topic. Finally while writting my blog I do my best to finish with a questions, a debate topic, a controversy or at least an opposing position in order to try to get my readers to think more about the topic.
And last but not least I reread and edit my post!
And then I do a google search for a picture to make it interesting!