We live in Dubai. Here are the 7 common mistakes we see first-time visitors make.

• We've lived in Dubai for three years and have seen first-time visitors make a lot of mistakes.
• If you're going to Dubai for the first time, keep your boarding pass and get your free SIM card.

Little can prepare anyone for what's in store when they land in Dubai.

We moved here from London three years ago and fell in love with the city's year-round sunshine, tax-free lifestyle, and futuristic appearance.

The skyline is crammed with towers that twist and turn in intricate shapes that seem to defy physics. At night, the city looks straight out of a sci-fi movie with a haze illuminated by the tips of skyscrapers.

You may spend so much time staring upward that you get a sore neck — but if you keep your feet on the ground, you can avoid these mistakes we see first-time visitors make often.

Don't forget to ask immigration for your free SIM card

Dubai is part of the United Arab Emirates (UAE), which isn't covered by many cellphone roaming packages unless you pay extra.

Fortunately, visitors at Dubai International Airport or Al Maktoum International Airport can get free SIM cards at the airport. Just ask passport-control staff.

Cards come with a local number and a gigabyte of data that can be used for 24 hours. Once that data runs out, it can be recharged or upgraded with tourist packages at an extra cost.

If you fly Emirates, keep your boarding pass to use for discounts

If you fly into Dubai on the national carrier Emirates before the end of September, your boarding pass will unlock deals at shops, restaurants, and attractions across the city.

The discounts aren't to be sniffed at and include 20% off tickets to Aquaventure, the world's largest water park, and 30% off "La Perle by Dragone," a Vegas-style show from one of the leading lights behind Cirque du Soleil.

If you're using a mobile boarding pass, take a screenshot in case it disappears from your account after your flight.

There's no need to bring a phrase book

Fluent English is spoken across Dubai, and many signs are in English.

After all, it's a very international city. Nearly 90% of Dubai residents are ex-pats, including many English speakers from the US and the UK.

Since we moved here, we've asked people for directions and advice countless times, and not once have we found someone who couldn't speak English.

Don't think you need to be a millionaire to visit Dubai

One of the biggest misconceptions about Dubai is that you need to be rich to visit.

But you can stay like a king for a low rate in places like the palatial Palazzo Versace hotel, where rates start at just 609 dirhams (about $165) a night throughout August.

How about the luxurious Marriott Lapita, which is inspired by a Polynesian beach resort? Book for only 423 dirhams a night in August.

Plus, that rate includes tickets to the local theme parks with lands based on Dreamworks hits like Shrek and Kung Fu Panda. (If you visit, don't pay extra for line-cutting passes. We've been many times, and they rarely get crowded.)

No need to ball out to see the sights — Dubai has amazing free attractions

On a related note, there are a lot of great things to do in Dubai for free.

"Imagine," an epic show that rivals anything at Disney's parks, plays at Festival City Mall several times a night for free.

It features flamethrowers, multicolored fountains, and lasers synchronized to scenes beamed onto a 36-story hotel and screens formed from fountains that fan out into a fine mist.

On the outskirts of Dubai, see the world's biggest 360-degree projection show in Expo City for free. It features dizzying scenes that swirl around the dome as you stand in the middle of it.

Think The Sphere in Las Vegas but the show is all around you.

It's easy to get tired in the Dubai Mall if you don't book any free ride services

The Dubai Mall is one of the biggest in the world, with more than 1,200 stores spread over millions of square feet.

It's so big that it even has a full-size ice rink, a Kidzania theme park, an amusement park, and one of the world's biggest aquariums.

A well-worn pair of shoes is essential, but if you still can't bear the thought of walking around it, book the mall's free chauffeur service for rides around the complex.

If you've got young kids in tow, you can also rent a stroller at no cost.

Don't worry much about pickpockets here — but be aware of strict local laws

The UAE regularly ranks second on lists of the world's safest countries. You only have to spend a few hours in Dubai to see why.

When we first moved here, we were astounded to see people leaving their phones charging in sockets outside shops as they went inside to browse.

It's also common for people to leave their handbags on tables in busy food courts to hold their seats while they order. Open-top supercars worth millions are regularly left parked on the streets at night.

That said, the country has a zero-tolerance policy on crime and strict laws, which are also important to be aware of before you travel to Dubai.

For example, homosexuality is illegal in the UAE, and swearing or displaying affection in public can be punishable by law.