Let's say you want to track your Projects with Marketing Referrals or Lead Warmth. You can utilize the Internal Notes section to capture this information on a Project.
First, click on Add Notes in your Project
Then, edit the Project and add the Internal Notes you want to track on your Projects.
Then, click on the Projects tab and customize your Project List with the Internal Notes Custom Column.
Here's more about how to customize your Custom Columns.
Once you add your Internal Notes as a Custom Column you will be able to sort your Quote by the Internal Notes.