First of all, I had a completely unrelated website to any product available on the networks. My website is about ethnic haircare and hairstyles. I used that website to apply.
You do have to talk to them so be prepared with your answers. I called 2 of the networks, 4 called me and 1 approved me without talking to them. They sent their decision by email.
Some asked me why I wanted to join their network. I said I was making money with Clickbank and Commission Junction and it was time to move toward CPA. If asked how I heard of them I said I was in a cpa marketing bootcamp and they were recommended. One guy was really impressed by this.
They will ask you how you plan to drive traffic. (I am doing article marketing.) I told them I was going to run ppc direct linking and also use SEO. I was asked if my website was the one I was going to use and I said no, I would build sites around specific offers, which is what I do.
They will ask if traffic is incentivized and you should say no. Most networks do not allow this.
They will ask what your daily ppc budget is. I said around $150.
They will ask what kind of offers you are interested in. I said trial offers because I learned that they seemed to convert really well.
That was about it. I plan to re-apply to those that rejected me and a few more at some point. But right now, I have plenty of offers to choose from with the 5 networks I belong to.
I hope this was helpful!