Start catching new team members early. You'll have more time to train them. [Skarmory gets a friendly wave of friendliness. If he wasn't working, he'd call out his Pokémon so they could say hi.] You can also ask breeders for advantageous eggs, but then you'd have to find someone with the Pokémon you want, and you'd have to pay them.

The pay is far from high, but the work is very easy. Also, I always know what is currently in stock and I learn tips and tricks about the different items. It helps when I shop for supplies.