To evolve your Pokémon there are two methods, one faster than the other. The first method is to capture many Pokémon as possible, even the same type. Each captures made will allow not only to gain experience, but also to gain specific to that Pokémon candy. These will be useful to increase the strength of Pokémon and after you have gathered the required number of candies you can decide to make it evolve. Find a wild Pokémon with an already high level will require less sweet to make it evolve. Warning: if you have the sweet needed to evolve Pokémon, but evolution is not successful, it is because it has not yet reached the required level.
The second way to evolve Pokémon is Pokémon GO Formation. This is done using the gym: If you approach a gym of his own team and his friend, you train your Pokémon in training that will allow them to gain experience points, advancing to level up evolution. Similarly, you can challenge others to defeat gym leaders and raising the level of your Pokémon in Pokémon GO.
Importance of evolution in Pokémon Go
Wait the opportunity
When it is advisable to make the evolutions? Although the temptation is to do it as soon as you need it, is increasingly chosen by more experienced coaches to do it in bulk by using a Lucky Egg that doubles the experience, not before level 15 or better 20, because then you really very difficult to go up to that point. So, instead, in half an hour of mass evolution it will be full of experience for access to increasingly powerful catches.