Your tips First of all it's better to travel during the dry season May-September. Few Spanish expressions are necessary Travelling by taxi cheap and convenient (fix the price before you enter). About staying in Lima people recommended us to stay in Miraflores, which is expensive but safe.
Lima for us was only the beginning of our journey. So we do not it much. We moved immediately to Cusco where the real trip has begun. On our list to do were the most well-know places like Machu Picchu, TIticaca, Arequipa Canion Colca, Ica (Huascaran and sandboarding), Islas Ballestas. In addition we went to the north from Lima, to Huaraz and Cordiliera Blanca. Awesome time, awesome nature. The life is cheap overthere, Spanish could be useful but some basic one can be enough.