I'm the only software developer at the company where I work. I was hired straight out of college, and I've been working here for several years. When I started, eveeryone was managing their own data as they saw fit (lots of filing cabinets).

Until recently, I've only been tasked with small standalone projects to help with simple workflows. In the beginning of the year I was asked to make a replacement for their HR software. I used SQL Server, Entity Framework, WPF, along with MVVM and Repository/Unit of work patterns.

It was a huge hit. I was very happy with how it went, and it was a very solid program. As such, my employer asked me to expand this program into a corporate dashboard that tracks all of their various corporate data domains (People, Salary, Vehicles/Assets, Statistics, etc.) I use integrated authentication, and due to the initial HR build, I can map users to people in positions, so I know who is who when they open the program, and I can show each person a customized dashboard given their work functions.

My concern is that I've never worked on such a large project. I'm planning, meeting with end users, developing, documenting, testing and deploying it on my own. I'm part way through the second addition, and I'm seeing that my code is getting disorganized. It's still programmed well, I'm just struggling with the organization of namespaces, classes and the database model.

Are there any good guidelines to follow that will help me keep everything straight? As I have it now, I have folders for Data, Repositories/Unit of Work, Views, View Models, XAML Resources and Miscellaneous Utilities. Should I make parent folders for each data domain? Should I make separate EF models per domain instead of the one I have for the entire database? Are there any standards out there for organizing large programs that span multiple data domains?

I would appreciate any suggestions.