You have a hard quest in front of you. Bancor is for me the best platform for instant trading erc20 tokens. It wont be easy for you to compete with existing good platforms!
Bancor is great. We actually use them some in our back end. They dont have the flexibility we have in listing new coins and even now we have a lot of coins they dont.
This looking very similar to Changelly but without fiat integration you have any plan to improve your services to add this function. What about affiliate program like they are offering to attract people to promote their link and spread words?
We are looking into options that would integrate fiat but we are unsure at this time how that will play out.
We will be adding affiliate options with one of our releases later this year.