How do you handle a project without a living style guide?
I would start by identifying two things:
- The basic style definitions such as typography, iconography, color palette and form elements. These are the most used items and understanding what is their basic look, behavior, and implementation will allow you to identify inconsistency and one-offs.
- The most used components, such as the headers, navigations, search tools, and depending on the app grid tables and list items.
By doing this you will help you to understand what are the patterns used and then you can continue designing and developing with those in mind. Also if inconsistencies arise, you can then discuss with your team decide what is the direction that should be followed moving forward.
With this information in hand you can then proceed to create a living style guide and decide with your team the strategy to maintain it and build it as you continue with more development.