Don’t Forget To Put Your Eggs In An Incubator
If you find eggs at Pokéstops, don’t forget to put them in an incubator!
A 10 km egg is more rare than a 5 km egg, and a 5 km egg is more rare than a 2 km egg.
You’re therefore much more likely to get bigger rewards from a 10 km egg than from a 2 km egg. So don’t forget!
Find More Pokémon Near Their Natural Habitat
You have a greater chance of finding Pokémon of certain types near their usual habitat.
I cannot confirm for deny if this works but apparently more water-type Pokémon near ponds and lakes, more grass-type Pokémon in the woods, and more dark-type Pokémon at night.