Read my previous article on the Ultimate Guide for Zaken and study the maps.
The 3 Zaken floors are identical, the only thing that changes is the position of the stairs on the side. You need to remember that each floor has 5 rooms. 1 in the center and 4 rooms around the central room.
When you first enter Zaken you enter from the lower right room. Since the stairs to the first floor are by the lower left room the best strategy to search the rooms is by doing a circle around the outer rooms:
Enter the first room (1) and do aoe, continue straight ahead to the next room (2) and aoe in the center. Turn left and go straight to the top left room (3), then turn left and continue straight ahead to the lower left room (4). This way you have checked all the outer rooms in a circle. Now you have the stairs to your right. Turn 180 degrees and go back but instead of entering the next room, at the barrels turn right to the central room (5). Aoe. Turn 180 degrees and go back to the barrels and turn left. Now you are back in the lower left room (4) with the stairs to your right. So turn right and go up the next floor.
On the second floor you are emerging at the top left room. The exit is at the lower left room. So you need to perform a circular search again. Enter the first room (1) and aoe. Go straight ahead to the next room (2). Then turn right and go to the next room (3). Then turn right and go to the next room (4). Now the stairs to the 3rd floor are straight ahead. But you still need to check the middle room. To check the middle room go back by making an 180 degree turn and at the barrels turn left. Aoe in the middle (5). Turn 180 degrees and go back to the barrels. Now turn right and you are again in the room with the stairs straight ahead (4). Go straight and up the stairs to the third floor.
Once on the third floor, you will make a clockwise circle again to search the rooms. Enter the first room and aoe (1). Go straigh to the next room (2). Turn right and go straight (3). Turn right and go straight (4). Now you have checked all the outer rooms. Only the central one is left. Go back, 180 degree turn and at the barrels turn left, now you are in the central room of the third floor (5). If you cant find Zaken here, it means you didn’t check your damage log well. If you need to search again, make sure not to lose your orientation. Don’t turn your character around. Keep in mind on which of your sides are the stairs. For example now the stairs that go downwards are diagonally to the left. So you turn left, go straight and turn right to find the first room. The stairs going down are to your left.
The trick in Zaken for not losing orientation, is to keep in mind where you came from, where the stairs are and where you are going. Don’t turn around, just make the 90 and 180 degree turns mechanically with your char. When you enter a room and go to the center, keep your char facing front. Make sure that you wont have to move to go save a noob that opened candles xD.
If you fear you will lose orientation, you can use Ariadnis trick: You can drop 1 adena in the first room. 2 adena in the second, 3 adena in the third etc. Just make sure that nobody from your party is going to either pick it up nor throw more adena on the floor because that kinda defeats the purpose :P.