ホモテナシ

Decide date (at least a month away) and guests, check for allergies and food preferences. You'd traditionally send the written invitation a few weeks before the 茶事, but for me, it is easiest to send the written invitation directly. This creates additional binding character, and people don't cancel last minute. The letter contains time, address, other guests and, for me, the explanation that the 前礼 can be done by phone.
Also book a friend for the general rehearsal about two weeks before.
Plan out the 茶事. For me, it works pretty well if I read the Almanac, write out a few seasonal words, decide on the overall structure of the 茶事, and then start to fill in the blanks. The 懐石 book is a good place to find more ideas, as well as my seasonal pages.

stage	plan
お白湯	(plain water if nothing special)
軸
棚	(if using; then also decide on 蓋置 and 水次)
釜	(and 風炉 or 炉縁)
炭道具	(香合, 炭斗)
味噌汁	(some seasonal ingredient that pairs with 味噌)
向付	(dish, and some light ingredient that makes a good start; usually 刺身 with some accent ingredient)
酒
碗物	(here, I find the 懐石 recipes too odd, so just a stately ingredient that can be cooked with some support vegetable. Citrus peel or 木の芽)
焼物	(easy, if you can't think of anything, just do grilled salmon)
箸洗	(if there's nothing that's seasonally particularly suitable, add a few pine nuts or a bit of 梅干)
八寸	(seasonal apéro nibbles, something from the water is usually harder to find)
香の物	(I like to recycle ingredients from above here)
主菓子
中立	(I don't have a gong, so find something appropriate instead)
濃茶	(if there's something special)
茶入	(I like to make a set of 御銘 with the 茶碗 and the 茶杓)
茶碗
茶杓
水指
建水
煙草盆
干菓子	(two types; again, I like to recycle something from the 懐石)
薄茶
薄茶器
薄茶碗
薄茶杓	(with a lighter name)

Order the stuff you need, in particular:
- 箸 (for the guests and for serving)
- 足袋
- 茶筅
- 茶巾
- any 道具 that might be missing
- any ingredients that need ordering
Start on the pickles if they need a long time
Try to have a dry run at least two weeks before
Two days before, get out all the 道具 (and their names and makers!), arrange them in the kitchen
One day before, clean room, house and garden, do the 灰型 if necessary, then pre-cook what you can:
- parched rice
- …
- shop ingredients
- also, look for flowers
On the morning before, clean the garden again, then start cooking. For me, it usually takes about 4 hours of preparation; and then I'd like to be still for about an hour. During this time, you can prepare:
- だし
- 味噌
- seasonal ingredient for 味噌汁
- 向付 (already plated)
- 碗物 ingredients
- 箸洗い liquid
- 八寸 (already plated)
- 香の物 (already plated)
- 主菓子 (already plated)
- 干菓子 (already plated)
- sieve teas
- prepare flowers
- prepare charcoals
45' before the 茶事 starts (and 30' before they arrive), 打水, launch charcoal; start warming ingredients.

Them	You
お白湯	lay starter charcoal; plate 味噌
香合拝見	launch rice
first tray	plate 碗物
飯器	start 焼物
碗物	plate 焼物, prepare charcoal for 後炭
焼物	打水
香の物	煙草盆
主菓子	prepare 中立
中立	check charcoal, clean room, put flowers
濃茶拝見	prepare 煙草盆
薄茶拝見	打水

井伊直弼: after the 茶事, the host should wait at the entry of the 露地 until the guests are out of sight. It would be a pity if the guests saw him close the gate, destroying all that was before. Then, the host shouldn't hurry, but return to the 茶実, and think back of the gathering, and maybe enjoy a bowl of tea himself.
Rodrigues in CQ80 gives an excellent account on what's the general procedure.
CQ82 describes how the first half of the 茶事, when the food is served, is governed by the principle of yin (darkness, secrecy); and the second half, by contrast, when the tea is served, by the principle of yang.

Larry explained in 22 that even though in Japan you can pay people to do it for you; the 灰型 (and cleaning of the toilet) are the minimum things that the host should do himself during a 茶事.

暁の茶事: The dawn 茶事, mainly done in 炉, according to the Almanac (though I would've thought that it might be nice to do this in the middle of summer…?). One of the highlights is watching the wet 釜 dry while 懐石 is served. It starts at 0400, so the host stays up all night to prepare.