I was hesitant to post this because it might get saturated. I am not sure how legal this is or if your competitor can sue you for this if they notice. But I have done it before. Please do me a favor and don't abuse this. Do an ahrefs search on your competitor Go to whoever is linking to them and send them an email in the email, say "Hi there. Please replace [competitor's link] with this link [your link] That's it. Ask and you shall receive.