Most theft in Europe is of the petty variety, rarely involving assault: the thief does not want a confrontation. Thus, by using your head you can prevent almost every potential crime. For example, don't let people listen in or somehow note your phone card or credit card number. Watch your credit card after giving it to a clerk: you don't want the clerk to make extra imprints. Review all charge slips before you sign them. And be careful with your charge card receipts: they have the card number on them too. In fact, you should destroy old carbons, billing statements, and other records that bear your account number.
Also, don't flaunt your money or act too much like a tourist. You know how foreigners stand out as targets for crime. Don't compromise your trip, but don't unnecessarily make yourself a bigger target. Be discreet when doing your thing in banks, at ATM machines, or at exchange booths. Take note of the people around you. Try to blend in and look confident. If you have a shoulder bag, wear the strap across the shoulder opposite the side on which the bag hangs. Be careful in crowded places such as those around street performers and on metros and buses: pickpockets love crowds—especially crowds ripe with tourists. Beware at beaches. If two people approach you, one speaking to you and the other hovering around, go on red alert: the speaker may be trying to distract you while the other person nabs an item. And never fall asleep with a valuable next to you. Move in groups when it's convenient. In no way is the danger great enough that you should modify your itinerary; just be smart, that's all.
The further south you go the more you need to be aware of your possessions and personal space. Beware of young vagrant children and their adult cohorts who hover around and pickpocket travelers. Such thieves may walk into you with an open newspaper or large flat box held extended from their waste, wave a newspaper in your face, or throw a baby doll into your arms to distract you while their accomplices rifle through your pockets. Other thieves may approach you with flowers or some other triviality to sell; simply brush them off—and don't feel bad about it. I've even heard of tourists being glopped with mustard then "assisted" by ostensibly helpful bystanders who in fact did the glopping and who point to the sky and claim the stuff is bird doo while they wipe it off and swipe what they can. No matter, if you're aware of their presence and have taken simple security precautions, thieves will leave you alone.
Thefts from vehicles occur rather frequently in Spain and Southern Italy. Regardless of where you are, leave nothing of value in the vehicle. Leave the glove compartment open and emptied. If a rear seat pulls down to offer access to the trunk, pull it down—and leave the trunk empty. If you must leave something of value in the trunk, however, lock that seat so it can't be pulled down. If possible, lock the trunk from the driver's side lock so it can't be popped open without the key. If your vehicle has a hatchback, remove the shield that conceals the empty trunk. Consider leaving the front passenger door open to allow thieves easy access: otherwise, they'll break a lock or window. Essentially, make the scene look as if some other thief has been there already. If you drive into the larger cities, consider parking in front of embassies and banks where security may be better, or in an area where traffic police are working. Throughout Europe, parking ramps offer safer haven than the streets; but they may not be worth the cost.
The rate of theft of vehicles themselves is high in the city of Prague and in Poland. The nicer your vehicle the more you should consider parking it in secure parking garges only. You may even be smart to leave the vehicle in an outlying smaller town or city, opting to take the extremely cheap trains into the metro area. Thieves concentrate where the tourists are, and the tourists usually aren't in the small towns. Turning the wheels all the way to the curb may also help prevent theft of the vehicle.
Some thieves are more aggressive than those I've mentioned so far. Keep your vehicle's doors locked when driving, and keep the vehicle in gear at a stop. If someone points to your tires as if indicating that the tires are flat, don't get out to look. If someone bumps you—especially if they bump you repeatedly—think twice before unlocking the doors and getting out of the vehicle. Rather, turn on your vehicle's hazard lights to signal that you're not fleeing, and drive slowly to a well-populated and well-lit place. Beware if you pick up a rental car at Madrid's airport. The rental companies there park their vehicles in unprotected and unsupervised areas. As a result, thieves have learned to puncture the tires, wait outside, follow exiting vehicles, and rob them when the unsuspecting driver pulls over with a flat. Always be wary of an offer of roadside help extended by anyone other than a uniformed police officer or civil guard. If a person stops to help, ask them to call the police. Conversely, don't you stop to help a stranded motorist: in the more marginal parts of Europe, roadside brigands are known to feign car trouble then steal your vehicle and/or rob you when you stop to help.
Lock away your baggage overnight, and lock the door to your room as well. When staying in a hostel, take a hint from nature and sleep with your valuables between your legs. Out of sight is out of mind; don't unnecessarily tempt thieves. Passports are a valuable commodity on the black market—keep yours secure. If you travel in a couchette on an overnight train, tie the door shut: thieves payoff conductors, put sleeping gas into compartments, and proceed to pilfer the unconscious occupants' possessions; if you're not careful, you'll wake up minus one suitcase or backpack but plus one big head ache. Italian trains have become infamous for such robberies. If something of yours does get stolen from your person, vehicle, or room and if you have some form of insurance to cover the theft of the item, make sure you get a police report at the next convenient opportunity, if you know what I mean.
And don't give up items for lost if they are stolen. Often thieves are only after cash and will dump wallets and other articles. Many are nice enough to throw the wallet—including credit cards—in a mailbox. The post will check your identification and deliver the wallet and contents either directly to your embassy or to the police who will forward it to your embassy. And police stations in Europe are often rife with stolen articles waiting to be claimed. If you've written your address on your articles, they may conveniently show up at your embassy like your wallet.
I'm afraid this discussion paints a rather disturbing picture. But things really aren't so bad. I just have to unload on you here to keep my conscience clear. Honestly, these dangers do not amount to an excuse for not following through on your plans to drive Europe.