First you need to understand the API economy and the game you will participate in. The customers and the acquisition channel are different.
Second you need to identify which products and services need to be exposed as APIs: this is a business decision and it has to jointly be defined by the business and IT.
Third you must establish your API Technology infrastructure. This is a job for Enterprise Architecture and IT to build what will fit your business and your ambitions within the industry.
I wrote an article to get into the topic:
