I don't think anyone can actually answer your question if you're not telling us where in the USA you're visiting. This place is enormous, and the culture isn't homogeneous.

If you go to NYC a slice of pizza is all you need to fuel your entire day.

Assuming this isn't satire... It really depends on where you're going. Assuming you'll be in a big city, I'd say it's pretty comparable to London. Don't go walking along vacant streets at night, or during the day if the area gives you bad vibes. Avoid confrontation with anyone looking to start some shit. In big crowds I like to keep my wallet and phone in a front or otherwise harder-to-access pocket.

All that being said, most tourist areas are quite safe.

Don't take your real phone with you. Just get a cheap burner phone that you can reset after customs went through it.

There really is no such thing as 'The USA.'

I live in New York City and what's cool here will get you arrested in other places.

Some towns are fine with you having a rifle on open display. Some towns are fine with you smoking pot on the street.

USA is really quite safe, just remember to not be black or a woman

Oh and wear a ballistics vest if you're going anywhere near a school

when you stub your toe you get heroin

Don't try to bring food. I've seen people stopped for smuggling meat. You're probably okay with packaged sweets or chocolate, but you should declare it.

Don't be fooled into thinking you can get tea if you see it offered. It may be some strange flavour, or very weak, or iced, or all three. And it will be hard to explain that you want milk and sugar with it.

Biscuits are good enough, but chocolate is rough.

And, of course, a "biscuit" will mean a type of savory scone.

If your shop, at most stores they will pack shopping bags for you and are a little shocked and overly grateful if you do it yourself.

Be prepared to tip in many circumstances (but not, oddly enough, for having your groceries packed).

Be prepared to be asked about football, the Beatles, the Queen, maybe even the King.

Don't be offended is someone attempts to do a British accent at you, it's meant as a friendly greeting.

If driving:

Four-way stops are like roundabouts without the roundabout. But with stop signs.

Pedestrians are not expected to look out for traffic, but are not allowed to just cross anywhere. So it balances out.

Someone has stolen the clutch pedals from all the cars.

Remember not to be black.

Be sure to tell them their life would've been much better today if they remained a colony

Don't forget your gun. America is extremely dangerous but only if you're unarmed. All the criminals and cops can smell if you have a gun and they'll be too afraid to do anything to you if you have one.

Also you can't trust our water, so it's purely Soda and Budweiser while you're here. Locals might tell you to eat at local restaurants but their stomachs are habituated. You'll need to stick to McDonald's. Luckily there is one on every single corner.

If you get injured you should avoid using an ambulance as they will take you directly to a hospital. In the US that's just where we go to die. You need to drive yourself to an Urgent Care doctor. If you can't drive yourself and have to use an ambulance then there is a complimentary memorial wreath that can be sent to your family. Along with the invoice for your death care of course.

The US is smaller than it appears on maps. This is because most maps are not American centric and have to expand the US to show the ratio properly. You might have budgeted multiple days to travel between the coasts but you really can just do New York one day and the Grand Canyon the next day.

Did I miss anything? Oh yeah it's traditional to make a bomb joke with the customs agent as you come into the country. Especially if you can manage a middle eastern accent. All of us do it. It's a grand joke.

Bring a printed copy of your ESTA / visa for immigration. Get some kind of travel insurance that covers health emergencies, and have proof of that printed as well.

I recommend travel health insurance. It's affordable and a good piece of mind considering their healthcare can be extremely expensive.

Never take the ambulance. They will suck your money and your soul.

They're driving on the right side.

Hello fellow Brit.

Everything is bigger. That's an obvious statement, but the knock on effect is that nobody seems to have a sense of "nearby". I frequently went out running on the pavement around two or three blocks, and people either looked at me as if I was possessed, or honked their horns like a "run Forrest run!" type thing because there was literally nobody else out putting miles on tarmac.

Retail parks are a cracking example. I was out with a friend who knew the area well, and we wanted to go from one store at one end of the retail park to the other. I was happy to walk the three or four hundred metres and back, but they were positively horrified at the thought of not taking the car to another parking spot there.

Speaking of driving - know your rules. Four way intersections are a cool invention. ~~Roundabouts~~ traffic circles are fucking wild going in from the right.

See those 300, 200, 100yd marker boards on A-roads and motorways allowing you to figure out what lane you need to be in to take your slip road? Purely optional in the US. Be ready for people in lane three (or four, or five, or six) to see their exit and cut straight across. Blind spot checking is for nerds and communists.

Things have changed lately, but go out with two or three changes of clothes, and that's it. The clothes in the US are generally much cooler and much cheaper, it's a good excuse to get new gear. Depending on where you're going though, it's hard work getting particular stuff - asking for Under Armour's heatgear stuff if you go running in winter will get you some real fuckin' weird looks in Florida, where even the vests are sometimes hotter than a duffle coat.

The border: know your shit - where you're going, how much you got, who you're with. The border force agents (whatever their unit is called) are generally super cool, but they ask super intrusive questions. That Marks and Spencer ham baguette you got in Gatwick/Edinburgh/Manchester? Eat it quick, because it isn't going through customs.

Not sure how long you're going for, but get a Post Office multi-currency card, or a credit card that specialises in the US Dollar or low international currency fees. While you're at it, feel free to wow them with contactless payments. Last time I went to CVS, I had tapped the card before the cashier had finished his spiel about swiping the card, and refused to believe I'd actually paid for a few seconds. It's like a magic trick with none of the effort.

Overt generosity is mostly viewed suspiciously. I left the DC metro system at a gate, and tried to hand off my all-day travel card for someone else to use for the day, and was looked at like I'd shit on their station concourse and drew a Greek flag in it. It's not like the tube.

Tylenol: get shitloads. It's basically paracetemol wrapped in bubblegum. Outstanding for hangovers.

Enjoy it! The Americans are friendly enough even if the majority of them make some pretty wack political choices, but that's another discussion. They're generally sound as fuck, and find the British accent something of a novelty, so feel free to use it as a get out of jail card if you make a social faux pas. (edit: I don't mean literally, I haven't tried it on police officers)

Have fun, let us know how you get on!

Where in the USA are you going. Saying you're going to the USA is like saying you're going to europe. There's a vast difference between the different states and regions within those states.

The Queen is still alive and we have her. Just don't tell anyone, okay?

My condolences

If you want to avoid getting shot, you should now wear a red hat, not a red coat.