Even by Rank 2, we have no way of knowing which direction your Settlement has started to take. Whether you're focused on self-sufficiency, trade or defense, all Rank 2 Sovereigns have one thing in common: what districts are currently available to them. Getting to Rank 3 will take a while and you'll want to build districts that will fit well into your settlement. Depending on your goals, some districts will be vital while others are more valuable to you left un-built.
Town Square - If you're Settlement has reached Rank 2, you've built the Town Square. This default district unlocks the rest of the Rank 2 districts and you can't get above Rank 1 without it. This is also your first member of the Department of Religion. The Town Square is an incredibly supportive district. It provides a good place to cluster your peasant-housing Cottages. The main Courthouse provides Prison cells, a place to Vote, and enhances the profit from local Income buildings. The Exclusive Barber Shops are hard to build, requiring Glass, but are eventually a good source of Litra, Tinctures, and local Health.
Main Gate - The Main Gate is your second opportunity to build a Defensive District. This handy 'district' consists of a giant gate that will fit into the rest of your wall structures, become your main access point if any walls are built. This giant gate, the Barbican is a multi-purpose defense building, damaging the Might and Celerity of attacking units, providing a universal Security bonus and crafting Sandstone into Bricks to top it all off. Every exclusive Guardpost increases Security settlement-wide, as well as providing additional cells for imprisoned players. It should be noted that all of the Main Gate buildings require materials a normal Rank 2 Sovereign cannot yet produce independently. Players in this district can perform Guard Duty, increasing local Defense for an upkeep cycle.
High Street - The High Street, along with it's Rank-neighbor the Stockyards are your first members of the Department of Commerce. Buildings in these districts are likely to increase Prosperity and lower Security. The General Store, central to the High Street, is your first option to craft Accessories, if you had the materials and characters of high enough level to equip one. This building also recruits Carts and reduces settlement consumption of Groceries. The popular Pub can only be built in the High Street. It sells beer to ballad-loving Peasants and offers Players a place to sleep where they can constantly smell stale beer and hear drunken ballad singing. The Grocer and primary way to transform Produce into Groceries is the Linked building. Players visiting the High Street can join in the constant commerce and Work in a Shop for a share of random goods.
Stockyards - If you want meat and/or have too many animals, the Stockyards is the way to go. Of course, that's if you have the Silver Thalers to build the first level of Auction House, it's main building. The Auction House takes extra Livestock and processes them into valuable Pack Animals. The Exclusive building is the Abattoir, a special butcher shop that produces Leather from Livestock. Finally, the linked building is the Butcher Shop. This handy little building can produce Meat from Game, Livestock, Animals and Fledglings. If you want extra Meat for something and live in a settlement with a Stockyards, characters can perform Work in Abattoir. They only want the leather.
Mines - The Mines are perhaps the most vital part of your optional Rank 2 Districts. In this district (and only this districts) you can build the all-important Mineral Mine. This is the only building in the game that produces raw metals, allowing you to create your own weapons, armor, currency and other random stuff that requires ores. Of course, the main building is actually the Sorting Station, which requires fairly easy-to-acquire Sandstone to build and upgrade. This building processes Marble into Slabs, something you'll appreciate a great deal in the near future. It also boosts the production of it's Linked and Exclusive buildings, increases Prosperity and decreases settlement Health. All that rock dust. The linked building is the Quarry. You probably already have one in a spare district, but they work best in the Mines.
Getting to Rank 3
When your Sovereign character reaches Rank 3, you'll be ready to build your Marketplace. To do this, you'll need the materials for a Level 1 Forum ie: Bricks. Fortunately, you've got the Mines for your Quarries for the Sandstone. Where you build the Brickmakers is your business.