Wearing Them Down
Wearing down the Pokemon you're battling is the first thing you should try before dealing with special Poke Balls, status effects or Action Replay cheats. While higher-level Pokemon and Legendary Pokemon may prove difficult with this method alone, it works well for most Pokemon you'll battle in "SoulSilver." Get the wild Pokemon's health low and when they're primed for catching, their life bar will turn red. Be careful not to accidentally defeat the Pokemon while lowering its health. Ensure you don't by using a weak Pokemon or move against it that only takes away a few hit points per move.
Poke Balls
Whenever you want to catch a Pokemon in "Pokemon SoulSilver," you use a Poke Ball. The game has 25 different types of Poke Ball. The Great Balls are 1.5-times as effective as normal Poke Balls, while Ultra Balls work twice as often. Some balls are designed for catching specific Pokemon. The Lure Ball increases your odds threefold when you use it on a water Pokemon, while it acts like a normal Poke Ball when used on a land-based Pokemon.
Status Effects
Status effects prove useful both for wearing Pokemon down and catching them. With moves like Poison, Paralysis, Burn, Sleep, Freeze and Confuse, status effects usually either hurt your opponent every turn or prevent them from performing moves. You've got a higher chance of catching a Pokemon if particular status effects affect it, especially Sleep and Freeze. Not only do these two make catching Pokemon easier, they prevent Pokemon from fleeing battle, which they sometimes try when their health is low.
Action Replay
The Action Replay is a cheating device that alters the code within the game to produce a desired effect. While this provides the easiest methods for catching Pokemon, it requires the additional purchase of an Action Replay. The "Easy Captures" code ensures that you catch every wild Pokemon you throw a Poke Ball at. The official Action Replay website, CodeJunkies.com, also offers a code letting you catch other trainers' Pokemon, something the game doesn't regularly allow. Alternately, another code gives you 900 Master Balls, which automatically catch any wild Pokemon they're thrown at.