Destiny Knot
When breeding Pokémon the offspring automatically inherits three random IVs from the parents. However, if you have one of the parents hold a Destiny Knot while breeding the offspring will instead inherit five random IVs from the parents. It does not matter which parent holds the Destiny Knot, either way there will be five randomly selected IVs passed down.
For example: If you have a perfect, 6 IV Ditto and you breed that with another Pokémon with 0 IVs in every stat there is a chance the offspring will have 5 stats perfect IVs, 5 stats with 0 IVs, or anything in between such as: 31/0/31/0/31/19.
Abilities
Starting in Black 2 and White 2, there is now an 80% chance that the female parent will pass down it's ability to the offspring. This does not apply if Ditto is used as either parent.
For example: If you breed a female, Anticipation Eevee with a male Pikachu there is a 80% chance the resulting Eevee will have Anticipation and a 20% chance the offspring will have either Run Away or Adaptability.
In Gen 6 if you want to breed a Pokémon to have it's hidden ability you can breed any Pokémon, including male or genderless (that has it's hidden ability) with Ditto, the offspring will automatically have it's hidden ability.
For example: If you breed a male, Technician Breloom with Ditto the Shroomish will automatically have the ability Quick Feet
Everstone
When you breeding if one of the Pokémon is holding an Everstone the offspring will automatically inherit the Nature of the parent holding the Everstone.
For example: You breed an Adamant Breloom with an Impish Ditto, if the Breloom is holding an Everstone then the resulting Shroomish will be Adamant Nature.
Hope this helped. If you need any more help for breeding your ideal Pokémon here is a useful, user-created breeding guide: http://www.gamefaqs.com/boards/696959-pokemon-x/67604326