It can sometimes take a while to move up in ranks on Pokémon Go. If you’re like me, and you don’t have a lot of time, but enjoy playing Pokémon Go, then this is a great tip for you. While I am not Pokémon Go expert, here is my favorite way to rapidly gain lots of XP. You’ll need to devote a least 30 minutes for this to work.

Find a spot around town that has multiple PokéStops grouped together. You will need at least 2 PokéStops. The more PokéStops you can find grouped together, the better. You will want to make sure that you can interact with all of the PokéStops from the location where you are standing or sitting.
While I haven’t been able to confirm this as fact, I have noticed that Pokémon seem to spawn more frequently when you have a group of people in the same vicinity. (Please comment if you can confirm this). So grab some friends to go out with you. Don’t worry, they will be able to rapidly increase their XP as well.
Within your group, a few of you will need to activate a PokéStop module for each PokéStop within your interaction radius. Each person in your group does not need to activate a module. Your group only needs one module for each PokéStop. So, thank your friends that take one for the team and donate their module(s) for everyone’s benefit. Once you and your group activate the modules, the module will attract Pokémon every couple of minutes, at each PokéStop, for 30 minutes. That’s why you have more benefit with the more PokéStops you have. More PokéStops, with activated modules, means a faster Pokémon spawn rate. Note: Every new trainer starts off with two modules. More can be purchased in exchange for Poké Coins in the shop.
If you have incense in your bag, then go ahead and activate it. Incense works in a similar way as a PokéStop module. The difference is that incense will spawn Pokémon wherever you are. You do not need to be at a PokéStop for it to work. Also, the other difference, is that it only works for the person who activated it, unlike modules. Be sure to tell your friends to activate their incense as well, if they have any. Just like modules, incense works for 30 minutes and can be purchased in exchange for Poké Coins in the shop.
Activate a “Lucky Egg” from your bag. A lucky egg will double your XP for 30 minutes. And, you guessed it, lucky eggs can be purchased in exchange for Poké Coins in the shop.
Every 5 minutes, a PokéStop will reset and you will be allowed to spin the coin and collect more Poké Balls and other items. Do this as often as it will allow you. You will get double XP everytime you spin the coin. You will also likely need the extra Poké Balls it will give you.
When Pokémon spawn, catch all of them, even if you already have plenty of that particular Pokémon. You’ll learn why on #8.
In between spawning Pokémon, you will want to evolve any Pokémon that you can while your lucky egg is activated as you will get double XP. With an activated lucky egg you will get 2000 XP for evolving a new Pokémon, 1200 XP for catching a new Pokémon, 1000 XP for evolving a Pokémon you already have caught or evolved into, and 200 XP for catching any Pokémon. So now you have a great use for all those Rattata’s and Pidgey’s you’ve accumulated. Go ahead and evolve the lower level Pokémon like Rattata’s and Pidgey’s, even though you may not need them evolved for battling. The goal here is to gain XP.
When you catch a Pokémon that you already have, go ahead and immediately exchange the lower XP Pokémon, of that type, for candy. This will allow you to keep your list of Pokémon and your candies organized so can evolve a lot faster. Remember, you only have 30 minutes. You don’t want to be fiddling around trying to exchange 5 pidgey’s at once. Note: If you catch a Pokémon that has a high level of CP and/or HP, you may not want to exchange it as it can be beneficial to you later in the game. Keep that in mind.

Before you begin this whole procedure, make sure your Pokémon are tidy within the app, go ahead and exchange the ones you need to for candy for the same reasons mentioned in #9.

I would love to know how much XP and leveling up you did, in the comments!

Lastly, after 30 minutes you can restart the whole process. Enjoy.