James Serra recently posted this article on some of the things to keep in mind when moving from a relational data model mindset to a NoSQL model.

A big difference with Cosmos DB compared to a relational database is you will create a denormalized data model.  Take a person record for example.  You will embed all the information related to a person, such as their contact details and addresses, into a single JSON document.  Retrieving a complete person record from the database is now a single read operation against a single container and for a single item.  Updating a person record, with their contact details and addresses, is also a single write operation against a single item.  By denormalizing data, your application typically will have better read performance and write performance and allow for a scale-out architecture since you don’t need to join tables.