Useful info for visitors
Language. The official language of Ukraine by legislature is Ukrainian, however, the majority of population (about 60%) speak Russian as their first language. A vast majority of Ukrainians older than 30 don't speak any foreign languages and the same is true for many younger people (although you can find a bigger number of English speaking Ukrainians in age group of 18 to 25 years old). Hence, if you don't speak any Ukrainian and planning on a trip to Ukraine it would be wise for you to hire a professional interpreter to avoid language barrier. However, if you like challenges and want to try to get by on your own, you will find English/Ukrainian touristic phrase books available in most book shops.
Safety. Ukraine is a safe country in general and violent crime is rare. However things can be stolen from you in big towns if you are not careful enough. To avoid pocket picking keep your wallet and documents in inner pockets of your clothing. It is also wise to leave valuables in a security box at your hotel or rental apartment and carry passport copies rather than the original with you. If you want to do business in Ukraine hire a professional translator who will help you avoid language barrier and will assist you with legal paperwork and formalities that can at times get quite complicated.
Money. The official currency of Ukraine is called Gryvna UAH (also known as Hryvna). However, you can easily use US Dollars on the territory of Ukraine - most bigger restaurants, taxi drivers, interpreters and even people in clothing shops will gladly accept a payment in USD as Dollar is considered a much more stable currency and is used on the territory of Ukraine along with national currency quite a lot. However, you will need Hryvnas for payments in kiosks, food stores, smaller cafes and some other places and it's best to exchange some money into local currency when traveling to Ukraine. You can easily do that in any currency exchange office. The ones in train stations and airports will normally have a somewhat worse rate, so if you plan to exchange bigger amount of money where the rate will really make a difference, it will be wise for you to use one of the money exchange offices outside of a train station or airport.
ATM. VISA, MasterCard. Most bigger restaurants and shops in Ukraine will take VISA or MasterCard without any problems. However, you can only pay cash for taxi, translation services, items you buy in local flee markets or small shops or cafes. So always having some cash on you is a wise thing. ATM machines are plentiful in Ukraine's cities and towns. You can find them in the streets almost everywhere. They will normally charge you the commission of about $3 for each withdrawal, so it's wiser to withdraw bigger amounts of money in order not to pay for a new transaction every time.
Tipping. Tipping in restaurants or for touristic services like taxi and translations is customary in Ukraine. It is normally about 10% at a restaurant. For other touristic services you can feel free to leave (or not leave) whatever bonus you feel like, it is up to your own choice. Leaving tips for services is not a must and you normally tip someone providing the service only if you liked the service quality.
Cell phone communication. Ukraine's international code is +380. Ukraine's cell phone operators (Vodafone, KyivStar, Lifecell). They use GSM network for cell phone communications in Ukraine. GSM is compatible with most cell phone standards used in Europe but totally incompatible with American phones which mostly use CDMA standard of network. So you will hardly be able to use an American cell phone in Ukraine. However, you can purchase a local cell phone at a reasonable price (starting with $50) and get a prepaid card of one of local operators to use with it. Unless you are planning to stay in Ukraine for a very long term (over several months), you don't need to get a phone with a contract. It is very easy to fill up your Ukrainian mobile phone balance using prepaid cards. The major and most popular operators used in the country are KyivStar, Vodafone and Lifecell.
Internet. Finding an internet connection in bigger cities of Ukraine is very easy as most restaurants and cafes will have free Wi-Fi. Your hotel will also have Wi-Fi, but it can be either free or for an extra fee there. If the free Wi-Fi network at a restaurant or cafe will require a password to start the connection, just ask your waiter, and they will write down the password or enter it for you.
Voltage requirements. The electrical current in Ukraine is 220 volts AC, 50Hz and they use electrical 2 pronged, European-style circular shaped sockets/plugs for recharding electrical equipment. Try not to bring electrical equipment with American or Japanese-style recharge plugs but if that is the case with your phone or laptop, check if it can take the 220 volts (most do) and also purchase a plug adapter to make sure that you can plug it into the differently shaped, circular, European electrical outlets.
Medical help and prescription medicine. If you can avoid using medicare in Ukraine, better to do so. However, if you have serious medical problems it's best to use one of the private medical centers in Kyiv, Kharkiv or Odesa as state hospitals are unfortunately lacking good equipment and good specialists and doctors there will also expect bribes for their services. When you go to a private hospital you still need to ask your tour guide or some local people for references, as even some private hospitals might have bad reputation. Once you found a reputable private hospital, though, the bonus is all service prices are listed in price lists and you won't be expected to pay any bribes. Prices at a good medical center in one of Ukraine's major cities will normally be somewhat (but not a lot) cheaper than those in Western hospitals. Some medical services like those with dentistry and stem sell treatment can actually be provided on a very high level in Ukraine, and some Westerners come to Ukraine to get their dental work or stem sell injections done as prices for those are considerably lower here than in countries like USA, Canada and Australia. However, you absolutely NEED TO research in advance and very well know about the particular clinic, doctor and their reputation before making a decision to get any medical procedures in the country.
If you are on prescribed meds it's better to take them with you to Ukraine from your own country, as not all kinds of western pills and meds are licensed in Ukraine, hence they might not be available at local drug stores.
Food and water. Food in Ukraine is considered to be one of the best in Europe. You can get any sorts of it - from local foods to western brands. If you go for something you already know about and want western brands you will find them in big chain supermarkets which are many in big cities of Ukraine. Western brands of foods will cost more than they will in the West, though, due to import fees. You will also find many foods of local make in Ukrainian food stores and supermarkets, and those can be not any worse or better than western brands. You can also find restaurants offering of all sorts of cuisines in big Ukraine's cities. Food in most bigger restaurants is of very high quality, an average bill for a meal for 2 at a fine restaurant will normally be starting with $50-60 and can go many times higher depending on how inventive you are with wines and gourment dishes. However, you can also find a bunch of smaller cafes with good food at more reasonable prices, where you will normally pay around $30-40 for a full meal for two people.
Water in Ukraine isn't of the same standard as it is in Western countries. So please avoid drinking water from the tap. You can purchase carbonated or non-carbonated bottled drinking water from any food store or kiosk.
Transportation. Most drivers of public buses will have no clue of English so if you want to be adventurous and use public transportation in Ukraine, make sure you very well know the exact place you are going to. You will probably have to count the number of stops before the one you need, as the names of stops are not written out and not announced in English anywhere. However, it is very easy to find taxis in Ukraine. They will normally be parked up along the streets. You can also rent a car per/day, but driving in Ukraine is highly un-recommended to foreigners as Ukrainian drivers aren't the best at following traffic rules and Ukrainian traffic police are unfortunately into taking bribes. If you need a full day transportation availability a good idea will be to hire a full-time driver with a car on a per/day basis.