Doing tea, it is easy to forget about things outside of the tearoom. But it is a very important aspect of tea to take care also in the mizuya 水屋 (kitchen / preparation room).
Please note that there are many ways of doing things, what follows is only one of them.
Handling of dogu
Dogu should not be passed from hand to hand, it is safer and better to put it down on the tatami and let the other person pick it up again.
All items should be cleaned before and after they are used.
New Chasen should be brought in to the room without being cleaned, as the tines will unfold if they become wet. Old Chasen, on the other hand, should be cleaned and left damp. The black string should be neatly arranged and pointing towards the handle. After using a chasen for practice make sure that it is cleaned and that there is no spots of tea left.
Before using a Chawan you should soak it in water, which will prevent it from staining. This is especially important where the Chawan has a unglazed foot. This part will easily become black and dirty looking if the Chawan is not soaked in water before use.
Also during the winter season it is good the heat the Chawan in hot water just before bringing it in to the tearoom.
Should be placed on a tray, the ones furthest from the front of the tray should be on the right side, and those closest to the left. (Unless there is a important esthetic reason for it to be otherwise). Also one set of the sweets should be stacked neatly, the other should be piled or scattered. There should be enough sweets on the tray so that the guests can take two each (one of each kind) and there still be some left. It is best it it is an uneven number, for instance 3 and 4 if you have 2 guests.
Before using the Hishaku it should be soaked in water. It is nice if it can stay in water for a few minutes. That will prevent leakage.
For hakobi temae the Mizusashi should be filled 80%; for tana temae it should be filled 90%. Before bringing the Mizusashi in to the tearoom you should wipe the lid (both sides) and the lip so that there are no drops of water.
A Natsume should have a small mound of tea inside it. The top of the mound should be as high as where the lowest part of the lid is. The mound should be nice and round, and have a even edge in the bottom.