Most probably if you hear "What else?", the interviewer has asked you the question on brainstorming / creativity. The interviewer is testing if you'll get stuck or will be creative enough and possess business judgment.
Here is how you should answer these questions:
1) Ask an interview for a minute to think
2) Think of several buckets of ideas (e.g. scope / value proposition). Remember to think as big as possible
3) Narrow down to each bucket and generate as much ideas as possible (e.g. scope: vertical growth, horizontal growth, new products. Value proposition: additional services, improved quality, etc.)
4) Present the structure (buckets) and then your ideas
Creativity is in direct correlation with you business judgment that can be trained by solving various cases with partners / reading industry reports / reading about the typical case industries and functions (Retail, airlines, logistics, marketing, etc.)