During the research phase of any project, you'll want to analyse and compare the user flows of apps. This can help when either optimizing an existing service or generating ideas for the design of a new one. In this case it was used for the redesign of a carsharing app.
You will want to look at a number of apps. Don't just focus on those of direct competitors but also look at examples from other categories that had to address similar challenges. This will help you come up with different, more novel ideas for your app.
Define the relevant steps of the user flow.
Go through the user flow and record each step with a screenshot.
Lay out the screenshots as they happen on the board.
Use red and green sticky notes to describe pain points and positive features of the designs.
Mark features that are crucial to get the job done or that will help set your app apart from the competition as top features and collect them on a specific list.
Gather further relevant ideas that might not be part of the first iteration on a wishlist.