Pickpocketing and muggings are quite frequent, albeit the rate is lower than in most large South American cities. Still, caution is recommended. It's advisable not to travel in the downtown area wearing expensive-looking jewelry or watches, even during the day. Stay alert and be especially careful in all crowded areas. It is recommended to wear your backpack at the front of your body in crowded areas. If you have a laptop it can be relaxing being outside in a café doing some work but thieves may see you. For your own safety, go to an internet café if you need to be connected and leave your laptop at home. It will save you from losing it and it can save you from a violent attack from thieves.

For tourists or other "beginners" lacking experience in over-the-counter transactions with hard Chilean currency, you can reduce the chance of your wallet getting stolen by following some advice:

Separate coins and bills. Coins are frequently used when paying for public transport, newspapers or snacks, store them in a small handbag so that your bills will remain concealed.
CLP1000, CLP2000 and CLP5000 notes should be easily accessible. Notes of higher value should be stored in another, more secure place in your wallet so you don't accidentally pay 10000 pesos instead of 1000, for example. Chile's Central Bank is in the middle of replacing all notes and its size, so you can find two types of 5000, 10,000 and 20,000 notes, all of which have legal value and are to be accepted everywhere.
Do not reach for your wallet until the vendor tells you the price.

Chilean Carabineros (National Police) are very trustworthy - call 133 from any phone if you need emergency assistance. Some municipalities (such as Santiago or Las Condes) have private guards; however, they usually don't speak English. Do not try to bribe a carabinero, since it will get you into serious trouble! Unlike other South American police corps, Chilean Carabineros are very proud and honest, and bribery would be a serious offense against their creed.

Regarding driving conditions: Chilean drivers tend to be not as erratic and volatile as those in neighboring countries.

Avoid taking photographs of navy ships and buildings or other military buildings, ask first. If caught they have the right to arrest you and expect to get all your photos examined and erased; however, imprisonment is rare as officials understand you might not have noticed the warning because you don't know Spanish.

In case you insist on taking the pictures expect some questions about why you photographed. Chile lives in peace with its neighbors Argentina, Bolivia, and Peru, but the country is always preparing for an attack, which some Chileans think might happen since it's a small and narrow country compared to its bigger neighbor Argentina, for example.

Some cities like Punta Arenas are naval cities, so be extra careful when taking photographs. Some marines may speak little English, so point at the object you want to take a photo and say "si?" ("yes?"). If they reply with a "no", then it's better to just leave.

Emergency Numbers:
131 Ambulance
132 Firefighters
133 Carabineros (Police)

Stay healthy

In case of emergency, call 131.
In case of an accident you can also call Chilean firemen - Bomberos - dialing 132 - they tend to be the fastest ones to respond.
You can always call the police -carabineros - at 133 in case of an accident or if your life is at risk for any reason. Don't expect to have an operator who is fluent in English. 

Rabies, as well as most major diseases, have been eradicated from Chile.

Tap water is safe to drink, although bottled water is ubiquitous.

Chile suffers relatively frequent earthquakes. If you are caught in one, keep your calm, stay away from objects that may fall down, don't run, and unless the building you are at is literally falling down don't try to escape. All buildings in Chile made after 1960 must comply with strict building regulations and should withstand even the strongest of earthquakes, so during an earthquake you should protect yourself from anything that may fall down from ceilings or walls. If you have been on a very strong earthquake, expect to feel aftershocks for a few days after that. Chileans tend not to care about minor earthquakes and will at most make a comment such as "tembló?" and continue with their lives.