Your exploration of the stunning natural wonders of this country is likely to involve a good deal of walking, so make sure you have comfortable, lightweight shoes. You may want to consider a money belt, and leave expensive jewelry at home. Use common sense and don't flash your money or valuables around.
As in many countries some parts feel safer than others. Don't forget sunglasses and a sunhat, good sunscreen (we love the Riemann P20 range for 10 hour protection) and insect/mosquito repellent. We love the SCOTTeVEST travel jacket because it has over 23 pockets, removable sleeves and RFID protection.
Ensure you bring a versatile travel jacket. It keeps you warm in the cold, wicks away moisture when it's hot, and doesn't retain odours – even after prolonged wear.
light wool is a good choice to wear against your skin as it naturally helps to regulate your body temperature. a long-sleeved shirt and sweater in the winter.
Wear them with light layers such as a t-shirt or camisoles for the summer, and warmer ones e.g.
Jeans are always popular and will serve as a versatile base to your wardrobe. 
Casual clothes are going to work best here.