First let me be the first on Quora to welcome you to Beijing, my home town and the greatest city in the world!
However, let me also be honest, Beijing is a great city to visit, not so great for permanent (or long term) residence, especially for a westerner (I'm assume you're from America or a European country). It needs a lot of getting used to, and you really need to keep an open mind for its many culture quirks and weird local customs.
First on everyone's mind is air quality and pollution
. It's really... really bad.
Jon Stewart said it all. And people are joking about how Beijing is perfect for shooting horror films like Silent Hill without special fog effect. You need to buy air filter for your home, even you don't have respiratory problems, it's simply for your health so you won't die in your 40s due to lung cancer. (OK I'm exaggerating, but I was told Beijing residents do have a higher than normal lung cancer rate). Buy a humidifier too, because Beijing is very dry in winter and spring. Buy masks too. All of these are sold in Chinese stores, so you don't really need to buy them here and bring to China. Besides, it's probably cheaper to buy them locally. But better get them as soon as you settle down with your housing situation.
Pollution aside, living in Beijing is not that different from living in New York or San Francisco or any large metropolis. The public transportation is very convenient, and you almost certainly will get a bike. Most streets have bike designated lanes. Again, better buy a bike locally.
Almost forget: Beijing traffic can be hectic. Last time I was back, I didn't know how to cross a busy street, since no one follows the traffic light, and everyone drives/rides/walks like a crazy person who doesn't care about his/her own life. So the trick is "follow the crowd". If the crowd is crossing, follow it even the light it still green.
Beijing has really really good food, if you like Chinese (duh...) and Asian food. Beijing also features some really good western restaurants and fast food joints are EVERYWHERE. Don't worry about having burgers or cheese, we have plenty of those. There're also various ethnic food from all over the world. I'd say Beijing offers a lot more variety compare of San Francisco or LA. But like all local restaurants, you might need to spend time to look for them.
Street food might be tasty but I generally advise against it because of food safety. There has been some scary reports on street food stand and smaller restaurants using bad or even poisonous ingredients. Food is not that expensive there (unless you dine at those crazy high-end places), so better eat at reputable looking restaurants.
As for preparation, I really don't think you need anything special. If your health requires special medication, probably a good idea to stock some. But whatever you need, you can buy locally. Beijing has everything. A lot of girls buy make up in the states, but mostly because make up and luxury clothing are cheaper here.
Not speaking Chinese would be inconvenient, but if you are hired as a foreign employee or expert, most likely your company will provide a translator to help you deal with daily issues. And most younger people can speak English, they watch American TV shows and use iPhones. I have a friend who knows the Big Bang Theory more than I do. So if you are lost or need help, try to find one fashionably dressed young person, you should be fine. Oh and, everyone works in Starbucks speak fluent English, and they're more than happy to speak English with you. (I've tried this myself, I pretend not speaking Chinese in Starbucks, and every starbucks I've visited in Shang Hai, Beijing and Shenzhen can provide great English services.)
Beijing is a great great great... city despite its many shortcomings. People are more open minded and friendly (although they might come out a bit arrogant, just think about New Yorkers). You probably won't feel the "communist“ presence in every day life. But you won't be able to get on Facebook or YouTube. Quora is still accessible, so if you have more questions, just post them here.