Just look at the linking domains and then pages on this root, filter.
Then have a look at the top sites linking to them...
But then you still need to be able to recognise what a good linking site is, if all their top links are from "seodirectorylinks.com" "articleplace.com" + just all irrelevant sites then they aren't very good links to get.
The truth is really.. any real quality sites linking to competitors you wont be able to just get a link from them, you need to work out why they gave them a link and why they would give you one.
I am always ready to learn although I do not always like being taught. ~Winston Churchill