I wrote this detailed list of tips for my parents who are visiting me in the country. I am sharing it here so that it may hopefully help someone else who is traveling to Cambodia!
Airport
When you arrive in the Phnom Penh airport, you will follow the other westerners to buy a visa. It’s a very simple process. You’ll fill out a form with your passport number, select tourist visa, and go to the counter. You will give them your form and passport. You can give them an extra passport photo if you have one, or give them $2 to make a copy of your passport. (It’s probably cheaper to have them make a copy there if you don’t already have a spare photo at home to bring with you.) Then you will move down to the end of the counter and wait until they hold up your passport. You will pay $30 in cash, and now you have your visa.
Next you will go through the passport check. It is fast and they didn’t ask me any questions. Make sure you have plenty of blank pages in your passport b/c the visa takes up a whole page.
Then you can get your luggage from the carousel. I think you may through some kind of customs there, but I didn’t check any bags so I was able to just leave at that point. I also didn’t declare anything so maybe that’s why they didn’t check me. It was all very smooth and easy to figure out.
Once you walk outside, you can exchange some money. You can use your credit card and get dollars or riel. The exchange rate was pretty good compared to where I’ve seen elsewhere.
You can also get a phone or sim card if you want. There are a lot of options and I don’t think one is better than the other. I went to the guy that spoke the best English and didn’t have a long line (but did have some people buying from there). I asked the price first and also asked how good the coverage is around the country. You could buy an iPhone for $100 or a small nokia regular phone for $35. The phone I got is unlocked so you can use it in any country. I’m not sure how much a sim card is, I didn’t buy one. The sign said you can make calls to the US for 3cents/min but you have to have a sim card to do that otherwise it won’t work. I paid $10 to get enough calls & texting for a month or so.
Dara Airport Hotel

Dara Airport Hotel is a nice, western hotel, conveniently located near the airport. I highly recommend it as a starting point to get accustomed to the country. However, it is much more expensive than hotels further from the airport, so if you are more adventurous and want to save money, it would be better to go straight to the more touristy area by the riverfront.
Book online instead of upon arrival, because it is cheaper. Book directly through the hotel’s website because if you book through a third party, you may not be able to change your reservation.
Ahead of time, you should email the hotel and ask for a shuttle from the airport to the hotel. They will do this for free. You give them you flight info, and after you walk out of the airport someone will be waiting (they will hold up a sign with your name) to take you to the hotel.
Note: They will only do this one way. It is best to get the free shuttle from the airport to the hotel, because once you’ve been here for awhile you will be more used to arranging a tuk tuk.
The hotel itself is on the 5th floor of the building and above. When you arrive, they will take you up the elevator to the lobby on the 5th floor, and then you will check in. You will need to show your passport so they can make a copy (you can also show a copy and that is okay).
The room at the hotel is very nice, very modern & American. I think you can even drink the water and be okay (I don’t, but I accidentally did at first and I looked it up and I think it’s fine – haven’t felt sick anyway). Some notes about the hot water – the bathtub is very nice, but I have noticed that there is not much hot water at night. You could try to take a bath but it might be colder than you are used to (lukewarm, so a bit chilly to sit in). If you turn on the shower, be aware of where the shower head is pointed. It is a detachable nozzle and the first time I turned it on it sprayed the whole sink with all my stuff sitting on it. Ha. So just remember that if you can.
Breakfast is amazing, definitely plan to wake up in time for that (not sure how late it goes until – you can ask when you arrive). It’s a big buffet with every kind of (western and Asian) option, and it’s all included with your reservation!
If you want to visit the pool, you have to check in at the lobby through the doors in the hallway past the restaurant in order to get a towel. You can also buy a smoothie there. It’s made with rice milk, and I asked for no whey protein (but they still gave me a little). Pay with cash at the check-in desk.
The bar is very nice, and you can even order from the restaurant menu there. The happy hour is 4-8 and you can buy one drink (that is $4 or less – you can basically get beer or house wine) get one free. Small snacks are also included (peanuts, veggies, other things depending on the night).
In the restaurant and bar you can use the 15% discount that they gave you at check-in.
Food in the restaurant that we found was good, if you buy lunch & dinner, is Chinese fried rice (nasi goreng), sweet & sour pork, Singaporean chicken, American soup, hamburger, and chicken burger. The fries and ice cream are good too. Most of it is not Cambodian food, but it tastes good and is familiar and reliable.
The first five floors of the hotel building is a mall. It’s kinda fun to wander around. You could get some pants or a shirt for about $7, and they have nail and hair salons. There’s also a pretty good grocery store where you can get drinks, snacks, ice cream bar, razor, etc. It’s all pretty cheap. You could eat in the mall but the hotel food is really good so I would eat there while you can.
Phnom Penh

If you want to get a massage, there is a great place right across the street from the main lobby of the hotel building. It is called The Spa and looks pretty nice. It has English writing on the front door. You can walk right in and get service. A 60-minute Thai massage is $10. If you want more or less pressure, tell your masseuse and she will adjust to your liking.
To leave the hotel facility, you should take a tuk tuk, which is a 2-4 person coach attached to a motorbike. To get a tuk tuk from the Dara, you just walk outside the front of the building and ask one of the guys on the right side. They don’t speak much English so you will need written directions or the address of the place you want to go (you can use paper or a translation app inside the hotel). There is no wifi on the first level of the building so if you use an app you need to do it before you leave the 5th floor. I found it was best to have as much information as possible – an address written in English (or Khmer if possible), directions if you have them, and a saved photo or 2 or 3 of the area showing the destination.
There is enough English in Phnom Penh to get along fine. A lot of people speak a little bit of English, and some people (shop owners, tuk tuk drivers) speak more. Most of the staff at the Dara Airport Hotel and other nice hotels speak a decent amount of English.
Money is.. well I was going to say it was easy but it can be a little complicated. The part that’s easy is that you can use US dollars (usd) – pretty much anywhere. They don’t have change in usd less than a dollar, so if you need small change you will get it in riel. Sometimes you will get change in riel anyways because they don’t have any USD (though they will accept it).
Riel is confusing. The currency is in large amounts. 100 is their smallest bill. Usually you will use 10,000 or 20,000. Anything below 1,000 is pretty much worthless (well, it is small change – they don’t use coins, only bills. Fortunately, the lower worth bills are smaller, so you can more easily tell the difference between something worthwhile and small change). The bills have alphanumeric characters as well as cambodian characters – that is the part that throws me off. The 1 in their written language looks like a 9. Make sure to read the bottom side of the bill (not the main number at the top) to see how much it is worth.
Right now the exchange rate is somewhere around 4000 riel to 1usd. That makes 20,000 riel approximately equal to $5. That is conveniently also how much most tuk tuk rides are. This makes it easy to just pay with one bill.
I hope this was helpful for anyone planning to visit Phnom Penh or Cambodia! I will write another post later about traveling to some of the tourist sites. Enjoy your trip!!