What are the different ways you can market ICO?
Which all platforms and advertising agencies?
Who are the people who make an ICO successful?
How much upfront budget is normally being spend on ICO Marketing & Advertising?
As for your first question, I think marketing for an ICO is a special case of marketing in which you need to first focus on your landing page design and User Experience. At the same time, presence in social medias like Twitter and Reddit, as well as blogging on Medium is a must. and you need to create good relevant content on Medium and i think you can find examples of good content on other ICOs social media pages.
And do use Analytics for SEO purposes. it is another must.