The easiest way to level up in Pokemon Go is to catch as many Pidgey, Weedles, and Caterpie as you can, use a Lucky Egg, and then do a mass evolution to get double XP. Each evolution will get you a minimum of 1,000 XP (more if you haven't registered that Pokemon to the Pokedex yet), so it's critical to jam as many evolutions into the Lucky Egg's 30 minute time limit as you can.
On average, a Pokemon Go player is limited to between 60 and 70 evolutions during a Lucky Egg's time limit, in part due to the game having a 20 second or so animation that pops up whenever a Pokemon is evolved. However, a new "trick" is being passed around the Internet that offers a way to bypass that animation and save valuable time to evolve even more Pokemon. When evolving a Pokemon in Pokemon Go, players can close the app immediately after the evolution begins. When they re-open Pokemon Go, they'll have the XP and stronger Pokemon already in their account without wasting time on the overly long evolution animation and subsequent menus.
The key to this trick is that you need a phone that can re-load Pokemon Go quicker than the time it would take to sit through the game's evolution sequence. Most newer phones, like an iPhone 6S, can load Pokemon Go quickly, but players with older phones might want to do some time tests before committing a Lucky Egg to this test.
If players can shave off even a few seconds off the time it takes to evolve a Pokemon, this trick could translate into some major XP bonuses. For instance, if a player can evolve a Pokemon every 20 seconds, they'll get a minimum of 90,000 XP as opposed to the 72,000 XP they would get for evolving a Pokemon every 25 seconds. More importantly, this "trick" is totally legal and won't result in players getting banned or facing any other negative consequences.
Pokemon Go is due for another update next week, and it's possible that the game's load times or layout could change to make this trick obsolete. So, load up your lucky eggs and get evolving and let us know in the comments if this trick made any difference!
(via Pokemon Go Association)