1. Cite Your Sources
It's highly likely that at some time you'll want to refer to another article or blog post that you read online within your own blog post. While it's okay to copy a phrase or a few words without violating copyright laws, to stay within the rules of fair use, you must attribute the source where that quote came from. You should do this by citing the original author's name and the website or blog name where the quote was originally used along with a link back to the original source.
2. Ask Permission
While citing a few words or a phrase and attributing your source is acceptable under fair use laws, it's important to understand that fair use laws as they pertain to online content are still a gray area in courtrooms. If you plan to copy more than a few words or phrases, it's best to err on the side of caution and ask the original author for permission to republish their words (with proper attribution, of course) on your blog.
Asking permission also applies to the use of photos and images on your blog. Unless a photo or image you plan to use comes from a source that clearly gives permission for you to use it on your blog, you must ask the original photographer or designer for permission to use it on your blog (with proper attribution).
3. Play Nice
Just because your blog is yours doesn't mean you can have free rein to write anything you want without repercussions. Remember, the content on your blog is available for the world to see. Just as a reporter's words or a person's verbal words can be considered libel or slander, so can the words you use on your blog. Avoid legal entanglement by writing with a global audience in mind. You never know who might stumble upon your blog.