Obtain a Meowth. A Persian is also acceptable, but usually harder to catch (read below).
There are many methods for obtaining a Meowth. One is to throw a lot of Poké Balls at it. This usually works. If this fails, then you could try throwing a large net over it. (If you try this with a Persian, you may need to use a bigger net.)
Find a wall. Use any decent wall you can find – the bigger and sturdier, the better.
Stock up on PP Ups, Ethers and other PP-restoring moves. For ultimate efficiency, use a wall within a Pokémon Centre.
Have your Meowth use Pay Day on the wall as training! Scoop up the money after each attack. When it runs low on PP for the move, simply heal it back up!
Cover image courtesy of pokemon-life.com. Meowth image courtesy of Mitsuhiro Arita; The Pokémon Company.
Idea by curiousnathan.