good backlinks are do follow websites that is relevant to your niche and higher page ranking than yours, also some people require to paste their URL on your website to get a link back you can also try getting a link back from them, it's like sharing backlinks that can help to increase the ranking of your website, there are many ways to get backlinks, actually if you search for "do follow search engines" you can use these tools to find do follow blogs, like what other said, social bookmarking, article, forum and directories may help in getting backlinks.