My biggest party hint is to do as much as possible in advance. Search out recipes you can refrigerate over night, do a few hours in advance, etc.
My husband had always had this dream of dinners presented on the plate, in courses. I had to disabuse him of this notion -- the difference between an only child and a big family. If you're doing this sans servants for a large number of people, you never see your guests. So family-style service is best.
If freinds ask to help, let them! Sort out in your mind stuff you don't need to absolutely do yourself. Even if you don't need help, say, yeah, pour us each a glass of wine and keep me company.
For winter parties, I often have a huge pot(s) of thick soup/stew right on low on the stove, with stacked bowls and spoons next to the stove. Folk go in and help themselves. Chili of all sort (Cincinatti, NM green, traditional meat), split pea soup, beans, stews of all kinds.
Do all your cleaning a few days in advance, then let it go besides the last minute bathroom cleaning (i.e., toilets). Remember the kitchen will be a mess no matter what you do, so ... give up once you've got it clean.
The biggest thing is to give up host/ess anxiety. Lots of folk I know don't throw parties because they don't feel it will be perfect enough. They worry that guests won't get along. Some of it is learning a basic bit -- learn to introduce people to each other with ease, and a tad of information. The main things that have been said about my parties over the years are how relaxed the hosts are and the diversity of the guests. But high ranking officers have been tickled to meet my immigrant neighbors, staunch republicans interested to meet old hippies. If you're having fun, they will.
A libation before the first guest arrives always helps!