Here are a few things to bear in mind during your stay in Prague. First off, as in any modern European city, keep your wits about you and try to avoid looking too much like a tourist if at all possible. Central Prague is as safe - if not safer - than most large Western cities, but it always pays to be vigilant. Check with the tourist office before going for a midnight wander anywhere outside the centre.
Smoking is most definitely permitted in public spaces (except for public transport) and you should expect funny looks and withering put-downs if you ask someone to extinguish their cigarette outside a designated non-smoking area (such as those found in 99% of restaurants).
Service charges are rare in restaurants and cafes but check the bill just in case. Tipping is expected instead and 10% is considered to be the respectable amount.
The weather in summer is generally sunny and hot, with temperatures hovering around the high 20's C. Winter is very cold however, so if you're planning a romantic snowbound trip then don't forget to pack a hat, gloves, and some thermal underwear!
If you have a laptop then a cheaper alternative to using internet cafes is to log in to one of the many public wireless networks that exist in the city centre. At last count there are over 100 such hotspots so you should never be stuck without internet access. Most cafes advertise their free WiFi at the door.
Whilst businesses love the increased trade provided by large groups of tourists - stag, hen, football/rugby tours etc. - previous bad experiences have made the locals twitchy when confronted with large groups of (usually British) people hellbent on drunken oblivion. If you're coming as part of such a group then please remember that you're a guest in their city and that you should treat it, and them, with respect. If you don't then you'll soon find that local police won't be afraid to do the same to you.
Some suggestions for you when you are in Prague:
1) Don't change money on the streets. It's dangerous, it's illegal and it's more than likely counterfeit money.
2) Using taxis, always agree on a price before getting in the cab. Normal fare within the city is 100-200 crowns--500-600 to the airport. Never accept "It's according to the meter." Establish a price. We are happy to call a reliable cab for you, or arrange our private very nice cars who work for us and are seriouse. Never ask a cab to take you to a 'gentleman's club,' as they often get at least 1,000 crown commission per one poerson.
3) Very friendly girls or women with multiple children, who approach you on the streets are pick-pockets, protected by 'minders." Be very careful. Don't let them 'swarm' you with kids or into an alley. They are experts and are very dangerous.
4) The metros and trams are not free. Tickets are sold at all newspaper stands. A ticket is not vald unless you franked it in the yellow box at the entrance to the metro or the several yellow boxes on board the tram. Plain-clothes 'controllers' are liable to check you for a valid ticket at any time and the fines are high. Buy a one, two, three-day or one-month pass--they are very cheap, convenient and save you from a costly 'tourist' fine.
5) Prague, like most European cities, has pick-pockets. Never leave your bags unattended or coat with wallet on the back of your chair. Particularly mind your passport. Danger spots are seats near tram or metro doors, area of the Prague Castle, Old Town Square, Wenceslas Square, busy bars, etc. Be vigilant. NEVER leave a camera or cell-phone on a table.
6) All public noise is forbidden by law in Prague. This includes singing or any excessive rowdiness or noise. You will be asked to leave the bar--if you persist, they will call the police. This holds true on the streets as well, after leaving bars. Prague police are very intolerant on this issue.
7) Vandalism, loud, aggressive or threatening behavior are all very bad ideas. Prague police take a particularly serious view of this and are not famous for their sense of humour. But if you have any problem, dont wait and ask police to help you.
8) Telephone cards: Buy only Telefonica O2 phone cards (175 crowns at all newspaper kiosks). Do NOT buy SMART CARDS.
9) Changing money: Be very cautious at change offices, as what you see advertised is not always what you get. They only advertise the rate they SELL pounds or euros. Change your money at any bank, for safety and a good rate--or--best choice, use an ATM machine.
10) Some con artists pose as "Currency Inspectors." They will flash 'ID cards' and ask to inspect your money. NEVER DO THIS. There is NO SUCH PERSON as a currency inspector. If he persists, call for police--he will disappear immediately.
Above all, don't panic and have a good time. Prague is a beautiful and violence-free, absolutely safe city. However, like most big cities, it has a small minority of thieves and scam-artists. Don't be a victim.
Follow these 10 commandments and you'll have a trouble-free holiday always to be remembered. Ignore them and you're more likely to have a holiday you will never forget.