New Main Quest: Find a way inside the Boyle estate
New Optional Quest: Deliver a note to Lord Shaw: He's in a wolf-mask at the Boyle party
Right before you begin the mission proper, you will have the opportunity to learn a new obstacle, i.e. the tall boy. These are that move around on long, mechanical stilts and equipped with good, long-range weaponry. The most important piece of information is that you cannot eliminate them in a quiet way, so avoiding them is the best thing you can do about them. Note that their seeing range is much larger, but they, fortunately, follow predetermined paths, and a moment's observation is everything it takes to determine when it's safe to make another move.
I recommend that you start in a non-typical way, which is by exploring the river. You should, of course, watch out for piranhas that you should be escaping from by teleporting, with time hold. You may also eliminate them with your crossbow while standing on the bank, which makes things safer. The purpose of the actions described here, is to find a rune at the bottom of the river (the above screenshot).
Return to your starting point and start the exploration of the actual area of the Estate district. Take a look into the two caretaker's lodges, in which there are ammo and two Sokolov's health elixirs. In the area where there are a guard and a civilian (both of them need to neutralized if you want to explore the area more thoroughly) there are gold and a rewire tool.
The most important part in the location is the building shown in the above screenshot. You can get inside in two different ways, namely enter through the main entrance on the ground floor or Blink (teleport) to the rooftops, and enter through one of the windows on the higher floors.
Since the building is occupied by weepers, you need to watch your steps. Depending on your approach, you can either kill them, render them unconscious (e.g. with sleeping bolts) or go around them. In the case of the last one, I recommend that you rely on teleportation, possession or time hold You definitely need to explore the top floor room (the above screenshot) that is occupied by three weepers. You can find here gold, two Piero's spiritual remedies, a book, a bone charm and a rune.
This is not the end yet, because you can reach the remaining rooms of the main building over the rooftops and by jumping down onto the external balcony shown in the above screenshot. In there, there are gold and a book.