This is the quick guide to capturing Pokémon!
Pokémon captured have 3 methods:
Fully Healthy
Damaged
Fainted
Fully Healthy: Pokemon who are fully healthy remove 30 points from your roll when trying to capture them, UNLESS they are Frozen or Asleep.
Damaged: Pokemon who are damaged to 50% HP, is the base/average capture rate. [No +/-]
Fainted: Pokemon who are fainted are able to be captured without struggle, but experience -10% happiness/friendship with trainer.
One can interact with a Pokémon prior to battle/capture to build a bond with it, this allows one to capture them more easily. Each post spent interacting with the Pokémon is +2% Happiness/Friendliness, +10 to capture rate per 10% Happiness/Friendliness level.