Whether you are in any field, be it internet marketing or blogging, guest posting is really an important part. By doing this, you get more exposure, a quality backlink and you increase your website's traffic.
It also helps in increasing your website's ranking in Google and other search engines. I call it the best way to get quality backlinks. It is also great when you are building a brand or the brand's credibility.
If you're new to writing, then just improve your language skills, write at least two articles every day, show your articles to your friends or family members and ask them to point out mistakes, learn day by day and you will be writing great guest posts that will drive you more traffic to your blog.
If you don't know, Google will not allow you to copy and paste articles. So, write unique articles and you are good to go.