There are basically three factors that catch Pokémon. You need to use the best Pokeballs, reduce your target's HP as much as possible, and use status effects like Sleep or Paralyze. Sometimes using specialized Pokeballs like Net Balls or Dusk Ball will make it easier to catch certain Pokémon, but in my experience, it's all about HP and status effects.
How To Catch Pokémon More Easily | Tips for Catching Tricky Pokémon
To make catching Pokémon much easier, you'll need a Pokémon with two critical moves - False Sweep, and moves that can put your target to sleep or paralyze. Here are some options you can use.
Ningale & Ninjask | Slightly earlier method
Ninjask is a good early option that you'll find on Route 5. It's slightly easier to get than our next option, but it's not as good. Continue to the next entry for one of the best Pokémon to use for catching.
You can catch Ningale on Route 5 outside of Turffield. At level 10, this Pokémon gains False Sweep - a move that leaves Pokémon with 1 HP. You will find level 10 Ningale in the tall grass as a random "!" Encounter. The Leveled Ninjask also has False Swipe, but they are more difficult to find in the Stony Wilderness area in the Wilds.
Tarsal, Kirlia & Gallame | The best method
The best method I have found is to get yourself a gallery with False Swipe and hypnosis.
Start by catching Tarsal in the wild - this little Pokemon can be found in Dappled Grove, Rolling Fields, and South Lake Miloch - mostly in the southern part of the Wilderness.
Make sure to grab a Male Tarsal, then reach Level 20 to evolve into Kirlia. Then use a Dawn Stone on Kirlia to evolve into Gallame. This Pokémon can learn incredibly useful moves. False Balayage and Hypnosis.
- Tarsal / Kirlia learns hypnosis at level 9. This is a non-damaging move that puts enemies to sleep.
- Gallame learns False Sweep at level 23. This attack always leaves Pokémon with 1 HP.
Gallame can also learn the Thunder Punch, which is incredibly useful and often cripples the target. Later in the game, Thunder Punch will be available for sale at the Pokemon Center in Wyndon.
Finally, if you choose to breed Gallame, it is possible to get the Move Look Egg Mean, which prevents targets from running away. This is basically necessary for some of the more difficult Pokémon to catch. This is not necessary for Legendary Pokemon, so you can pass for Medium Look.
