Good question, I have some experience with that so here's what I think.
First arm yourself with knowledge. Information's are crucial. And I'm really serious about that, you need to know EVERYTHING. How to register , how to submit products, payments and shipping, prices and costs.
And always have a couple of examples of ECA's from their area or at least same country. A positive feedback from those people would help a lot.
Hope this helped.
xoxo