Firstly, start by obtaining a copy of the Standard.
The introduction of Annex SL, which establishes a consistent structure featuring 10 clauses as well as common terminology and definitions applicable to all ISO Management System Standards (MSS), is the biggest change contained within the ISO 9001:2015 document.
In parallel, research and read the communications from ISO and LRQA to understand the proposed transition guidance. ISO is intending to publish further transition guidance and also guidance for the interpretation and implementation of ISO 9001:2015.
Look at how your organisation already manages the new and significantly changed areas and how this relates to your quality or integrated management system.
Begin thinking about an outline plan and timings for when and how you will review your management system to gain a view of how well it relates to these new areas.
Think about training for yourself and your key people involved in the management system and about how their knowledge and skills may need to be developed to help your organisation through any changes.