Getting good topic to write on is the first step towards having great contents on your own blog. However, it is not as easy as you might think. Here's how I do it: When looking for good blog content, take a look at what's been in Google News related to your industry for the past few days and find items that you can respond or react cogently to. Not only will this help you find relevant topics to write about, it can also bring additional search traffic into the blog by ranking well (at least in the short term) for keywords related to the news story. Hope it will help.
I've got an entertainment site. When I'm lack of ideas what to write, I'll check Google Bar to see if there is anything special on that date. For example, yesterday was the 115 anniversary of Popeye the Sailor Man, and it is on Google Logo. I wrote about it in my personal blog, and get good traffic.
Actually the easiest is to rewrite news and add in some commentaries, with appropriate keywords and enough keyword density. Many news in major news network are not written with SEO in mind.