What is one of the biggest challenges you’ve faced on a project and how did you solve it?

I was assigned to a project at NAB which was in the banking regulatory domain. 
The project was going to start in a few days’ time. I was new to this domain and was really worried about the requirements phase. Interacting with the team without having any clue about the regulatory domain could have led to many issues. So, I decided to do something about it.

I obtained copies of APRA guides   there were many 
Reporting Standard ARS 322.0 Statement of Financial Position
  Reporting guidance RPG 701.0 Reporting Guidance - ABSRBA Reporting Concepts for the EFS Collection  Basis of consolidated reportingPDF124 KB

I went through the chapters diligently. Even though a few days was not sufficient, but I focused on learning the vocabularies and the processes, relevant to this project. This preparation helped me in understanding the key concepts, terms as well as processes. It helped me in the requirements phase and in building a good rapport with the teamr.