Brazil is a huge, sprawling country, with varying climates and geographical differences. Indeed, what you'll need during a trip to Brazil depends on whether you're heading to the north or south or if you're traveling in winter or summer. Picking the essentials to pack can be a tricky issue. It's important you check out the climate in the region you're visiting and choose clothes suited to the season.
If you're planning to vacation in the Amazon, bear in mind it's muggy and humid all year round. The temperature remains constant and it's more a question of how much it rains. It usually rains every day, which is actually very refreshing! It's not necessary to pack a waterproof jacket or umbrella, you just need to find shelter and wait for the shower to pass. Summer clothes are a good idea but take long sleeve t-shirts and pants for rainforest walks.
As for toiletries, Brazilians are renowned for their body care, so you'll be able to buy anything you need once you're there! Travel light! What's more, you don't need to take insect repellent, as you can find it, at a cheaper price, in all the towns.
Finally, Brazil's known for its flip flops and you'll find numerous brands that are well priced! If your luggage is limited, don't bother packing a pair - make the most of your trip to stock up on new ones, as you'll be spoilt for choice.