Before thinking about marketing an ICO, why not open an announcement thread and open a bounty campaign? This is just a suggestion. Don't even ask who are the people that makes an ICO successful because the ones who make an ICO a successful one is the concept, the team behind it and the investors as well. The normal budget being spent on ICO marketing and advertising for some ICO it is 30% of the tokens, for some 20% sometimes more. It depends on how much percent of you want to dedicate on the marketing and advertising.