Use this helpful tool to quickly advance in 'Pokémon GO'

    Any experienced "Pokémon GO" player will tell you that the   key to quickly leveling up your trainer is to evolve a bunch   of Pokémon while using an item called a   Lucky Egg.   Evolving a Pokémon normally earns you   500 XP points, making it one of the most lucrative actions   you can do in the game. Under the influence of a Lucky Egg, those   points double to 1,000 XP per evolution.   A website called   PidgeyCalc helps you figure out exactly when   to evolve a batch of Pokémon and the number of XP   points you'll gain with a Lucky Egg. It'll even tell you when you   should hold off on evolving and catch more creatures   instead.   For those looking to not waste a bunch of Pidgeys and   Weedles, it's a must-use tool.  

Pidgeys are one of the most common Pokémon in   the game, and they're great to evolve because they only need 12   candies. On PidgeyCalc, I entered how many Pidgeys   I had along with the number of candies I   had to evolve with. 

More here:

http://www.techinsider.io/pokemon-go-tool-helps-you-quickly-level-up-trainer-2016-7