Do keep it simple. Make your best dishes but that doesn't mean pulling out The Joy Of Cooking and spending for hours in the kitchen. If need be, buy a rotisserie chicken. After all, the dinner party is really about enjoying yourself.
Don't allow anything to look store bought. Please, for the love of god, take it out of the plastic container. If you must admit that you bought it, that is okay, but to not put it in a dish feels beyond lazy.
Do know the power of a good cheese plate. It's so easy to put together, and helps your guest from getting too hungry should your main course run late.
Don't be afraid to embrace the question "Can I bring anything?" Yes, you can! Wine is greatly appreciated and will lighten the grocery bill!
Do save the hard stuff for later in the evening. I have made this mistake before myself and it isn't a pretty one. It ended with a friend asleep at the table in a Honey Whiskey coma while another slurred inappropriate things about his sex life. We live, we learn, and now we only make Old Fashioneds with dessert.
Don't make it a big performance. Obviously, we want to impress our guest but you don't need fake lashes, heels, a soufflé, and 3-course meal. You just need to feed people and be yourself.
Do prep your home. Have the dish washer empty and the sink ready for scrubbing. There is nothing worse than having double the dishes because you didn't clean up beforehand. It makes the post-party clean-up feel super overwhelming.
Don't forget the music and ambience. Pick up flowers at the corner grocer, pull out the candles, and load up a playlist (Spotify has a hefty selection). It shouldn't take more than 10 minutes to set up but will set the mood for your evening.
Do consider themes. I may or may not have hosted Harry Potter dinners...not embarrassed at all. We enjoyed Butter Beer, English pies, and various flavored jelly beans. It was a great time. I've had friends do Valentine's Day brunches, Oscar parties, and must more. In fact, my ShopIstoria.com launch party is going to have a loose Scottish theme.
Don't forget to have fun. It's your home so be comfortable and show everyone that it's okay to relax. If you're not having a laugh, what was the point?