I write out the menu and stick it on the fridge. Then set out all the serving ware and serving
utensils so I'm not scrambling when it's time to plate.
After planning the menu, and I don't try out new recipes usually, although I'm breaking this rule Tuesday night, I write out the grocery list too, checking in the pantry for every item. This way you suddenly don't discover you are out of baking powder or something at the last minute.
Then I plan the timeline. I always plan to be done with the setup and as much prep as I can 30 minutes before the start time in case people come early. I would never show up early but people do!
My timeline is written with actual times, I start at what time I want to serve and work backwards, adding a 15-30 minute buffer. Such as roast in: 5:00 pm, check roast temp: 6:30 pm, roast out 6:30-7:00 pm, roast rest until 7:15 pm. It sounds really anal but after I have a glass of wine, the distraction of trying to cook and play hostess, and stay relaxed and smiling, I tend to forget what the heck I'm supposed to be doing. This is posted on the fridge too and some good friends will help me by saying, oh, it's xxx time, can I do that for you? Plus I cross stuff off as I go. It works for me!!
Plus I truly believe in the lipstick thing before people arrive. If all else fails you will look nice in the pictures. And for guys, just put on a fresh shirt in lieu of the lipstick. Not that I judge...