Peter,
Thanks for your answer.
To clarify, when I say "what I have been doing up to now..." I mean one day lol. I've just started doing this, I've no experience with contest creation.
Well, in fact, I've just got one reply of one prospect, so from the 10 emails sent, I've got 1 answer. That's a 10% effectiveness. I'm thinking on sending around 30 emails, so we'll see in a few days.
I hope to get a 20-40% success rate, just because I'm trying to get one tweet. We'll see in a few days.
About what you say, it's true that what matters is having a nice social following. But that takes a lot of time. Imagine that if I take a client (not this case), and they don't have too many followers, it's the same situation that I've got. Even if my client had lots of followers-fans, if they don't have good engagement rates (what Avinash Kaushik calls applause rate, amplification rate and conversation rate), then that doesn't matter at all.
Anyways, thanks for your answer!