Pokeballs and Status Ailments increase the catch rate of capturing a Pokemon.

ie. If you use Sleep Powder on Regirock, the catch rate is 2. With Ultra Ball (with a catch rate of *2) you have a catch rate of *4. Which means you have a higher chance to capture Pokemon. Don't forget to lower HP of wild Pokemon because this can be very effective.

Take note that an asterisk * means to multiply.

Pokeball Catch Rate:

• Pokeball *1
• Great Ball *1.5
• Ultra Ball *2
• Master Ball (100% Guaranteed Capture)
• Safari Ball *1.5
• Net Ball (If Water and/or Bug *3 -- If not Water and/or Bug *1)
• Dive Ball (If battled in water *3.5 -- If battled outside of water *1)
• Nest Ball (The higher your level, the more likely you will get a capture *1-3)
• Repeat Ball (If you captured the previous Pokemon *3 -- If you have not *1)
• Timer Ball (The catch rate grows better (of not used every turn then it resets to 0 count) as the battle continues *1-4)
• Luxury Ball (Makes the Pokemon Base Happiness 200 instead of 70) *1
• Premier Ball *1

Status Ailment Capture Rate:

• Normal Status - 1 (Low capture rate)
• Poison - 1.5 (Medium capture rate)
• Burn - 1.5 (Medium capture rate)
• Paralysis - 1.5 (Medium capture rate)
• Frozen - 2 (High capture rate)
• Sleep - 2 (High capture rate)

Health Capture Rate:

• Full health - 1
• Half Health - 1.5
• Critical Health (Red) - 2

With this, you will take an advantage of capturing a Pokemon within a few turns. I recommend using False Swipe to make HP down to 1 and use Sleep Powder or Hypnosis. This works with all versions (including old and new versions).