Thats a great question and even though I am ,newish, to the wholesaling end I hope this advice might help. I once read it's like the chicken and the egg senciaro. If you have a great deal and market it the buyers will come. If you have a great buyers list then eventually the sellers will come.
One tip I read and tried was a ghost ad. The REI mentor said post a ghost ad on craiglsit saying 3/1.5 in a great area minimal work great arv. Well I decided to do that once just to see what the outcome was....within an hour I had three different emails asking for more details on the property and if it still was available. Granted I did it once just to add onto my list, don't want to do it alot and get people thinking I'm making things up and not want to work with me. So where I am going with this is, if you have a deal and market it people will be interested.
I've built a list of ten great end buyers by basically reaching out to people and letting them know exactly who I am and what I do,no frills no b.s. I've also followed some great advice that I've read on here about a great way of building a buyers list.
I haven't had a deal yet, it's been about four months since I started seriously focusing on wholesaling. But that doesn't piss end buyers off. Because they know when I finally reach out to them with a deal it's going to be worth their time and a great deal. Hope this helps a little and I have the link for building and end buyers list below.
https://www.biggerpockets.com/forums/93/topics/40258-how-to-build-a-buyers-list-fast-28-ways