What is the best way to get stronger Pokemon in Pokemon Go?

The trick to playing Pokemon Go and getting strong Pokemon is focusing on leveling up your character.






 






Don't worry about powering up Pokemon until you are a higher level; you'll gain levels quickly—and you'll catch higher level Pokemon later.




 






So if the best way to get strong Pokemon is to level up your character, what is the best way to level up your character?
 
The best way to power level is to save all your Pidgeys, Weedles, Ratatas, etc. and then evolve them all at once when you have a lucky egg running.  A lucky egg doubles all XP you get for 30 minutes.




 






You get your first lucky egg at level 9, or you can buy one with real money.




 






I have done this three times now.  I saved a bunch of simple Pokemon and then evolved a ton of Pidgeys, Weedles, and Zubats. I went from level 11 to 14, and later from 17 to 19. With my final egg I leveled up from 20 to almost 21.




 






Now that I am at a higher level, I find Pokemon that are also at higher levels.  For example, when I was a lower-level character I had a Flareon and I invested a ton of Eevee candies/stardust into that Flareon, making it as strong as possible—about 800 cp.  But then two days later, after I power leveled and gained 5 levels, I caught an Eevee that was around 550 cp, evolved it, and without powering it up at all I got a 1200 cp Vaporeon. 
 
Don't make the same mistake I did.  Wait until you are a higher level before using your candies and dust to level up your Pokemon.