Team Rating is a measure of the overall power of your team. A Shiny new team should start with about 1,000 Team Rating. The total value in Gold Crowns as well as individual Player levels contribute to this rating. To reach 1,900 you will need to nearly double these factors.
This will take some time and a bit of luck. I have about 12 games played with my highest valued team and it is still below 1,700. Things that can help include: buying an Apothecary to avoid any unwanted deaths, having a surplus of players to level up evenly and saving your Gold Crowns.