Brazil is one of the least hassly countries I have ever lived in. The only thing that seems to put people off coming is the consistently bad press relating to violence and safety. You can't guarantee safety anywhere in the world, but here are some tips for keeping safe in Brazil:
1) Blend in. Thieves can see an ill-prepared tourist coming a mile off. You know the ones: those sporting the flashy jewellery, the camera round the neck, expensive bag, laptop computer etc.. Leave all your expensive stuff at home or in the pousada/hotel safe.
2) Carry any handbags/purses underarm and keep closed at all times.
3) Try to avoid answering your mobile phone or taking out a wallet/purse in the street.
4) Change before you go to the beach. Everyone can tell youre a tourist if you try to change clothes once you are there. Change where you are staying and just put a wrap or shorts/t-shirt on top. Ask for a beach towel to take with you and hire a beach chair or umbrella on the beach.
5) Never leave belongings unaccompanied- particularly if you are going swimming or buying a ticket at a bus station/airport.
6) Walk with confidence. Memorise the map before you go, or write major landmarks on a separate bit of paper, so you are aware of who is walking beside you and not distracted.
7) At least learn enough portuguese to ask for directions, and understand the response!
8) Inform credit card companies before you leave home and let them know you will be in Brazil, so your card doesnt get blocked and you suddenly have to find cash off the beaten track or late at night.
9) Only access ATMs during daylight hours when there are people around.
10) Only venture into a favela as part of an organized tour.
11) Carry cash in different pockets, so that if you do get pick-pocketed you dont lose everything.
12) Carry R$2 (around US$1) notes easily accessible, in case you need to pay porters, or parking.
13) Change money before you come, or at a cambio exchange house in the airport on arrival. Do not, whatever happens, change money with porters or taxi drivers.
14) Get a pre-paid airport taxi from your arrival airport, or better still organize a private taxi transfer via your pousada / hotel. It usually doesnt cost any more and you know you are being taken to the right place.
15) Always carry a xerox copy of your passport, drivers license, travel and medical insurance on you.
16) Don't take a big bag or purse if you are going dancing- or anywhere you think you may feel unsafe. Put all money/cards in pockets if possible.
17) Always take the address of where you are staying with you, and keep it separate from money and cards.
18) Never walk along, or beside, the beach at night in big cities.
19) Remember to take out travel insurance before you leave to cover any eventuality.
20) Always arrange at least the first few days accommodation in advance, whether it be hotel, hostel or pousada.