Resources like Ahrefs and Majestic can help. It’s not as really serious as it used to be should you overlook some while, since Google’s algorithm will discount nearly all identified spam inbound links automatically. See Rand Fishkin of SparkToro use this technique to get some good media awareness and http://whatarebacklinks49359.educationalimpactblog.com/16337107/the-best-side-of-how-to-create-backlinks-on-wikipedia