Free Online tools to find your competitors backlinks
If you know the list of those website from where your competitor got the link from then you can also get the backlink from those same websites/blogs. You can also write a good comment and can get a backlink from those websites which are are dofollow links just as your competitor would have done.
Here are some ways to earn links for your site that can get you started: Find some of your competitors and enter their domains into Open Site Explorer (OSE). What content of theirs is linked to and shared on social networks more than others? Is it a video? An infographic? A post about dinosaurs? You get the idea. Once you know what type of content is working for your competitors, you can work on creating something even better and sharing it out to the same folks that were sharing your competitor's content. Find all the sites that are linking to 404 pages that are on your competitor's sites. Are there a few 404 pages in particular that have a ton of links? If so, create a resource of your own and let the people linking to the 404 page know that their link is going to an errored page, but that you have something better. Find links that two or three of your competitors have, but you don't. If these people are linking to your competitors, then they ought to be linking to you too.
Here are 3 main tools you can use:
Smallseotools is one of the best online tools to find the backlinks of your competitor's sites. It will show all the links where the blog/website is linked along with it and also shows how many are then nofollow or dofollow links. It shows 10 results per page and a very nice tool to get backlinks of your competitor's website or blog.
Opensiteexplorer shows the way how a website or blog is linked to another website. It will also show the anchor text of your competitive website through which a website or blog is linked. It also shows the page authority and domain authority of the website where the website is connected.
It is enriched with few awesome tools and features like shows url rank, number of backlinks, top pages, anchor text, type of top level domain. It also shows the type of backlinks like text, dofollow, nofollow, sitewide, redirect or images. It will aloso show anchor phrases through which a website is connected or linked to by other website, along with it shows referring pages, referring domains for anchor phrases.