Stars Without Number has cool a game master resources section that gives names and a bit of cultural information on a variety of old earth ethnicities. Here is my take on Americans:
American male names
American female names
(i may replace the ending of most female names)
American place names
American names often include a "middle" given name, sometimes related to a relative's name or a figure of importance, it isn't unusual for this name to be drawn from a different language or to be archaic. Sometimes the a first name and middle name will be used in junction (such as "Billy-Ray").
Traditional american cuisine relies heavily on beef,chicken and Bar-B-Q as meats, potatoes, corn, veggies and cheese (sometimes pork or fish will be served). Common food includes sausages of dubious origin known as "hot dogs", "wieners" or "franks", hamburger and french fries (along with chips). Common condiments are ketchup, mayo, salsa, bar-B-Q sauce and mustard. Americans frequently serve cola, sweet-tea and beer with meals. American cuisine will faddishly adopt a new or foreign food and often forget about it inside of a generation. Veggies are typically smothered in cheese.
Cotton, Denim and Synthetic blends are used to produce jeans, jackets,shorts and tee's. Brimmed hats are popular as are knitted caps. "Western" styles flare up now and again as does the military look but these ebb and flow in popularity. It's not uncommon for jargon, slogans, pictures or advertisements to appear on American clothing. Popular footwear includes sandals and sneakers of all imaginable varieties and materials (often with clearly identifiable manufacturers' logos).