Step 2 - Pokémon, O-Powers and Organization

After getting the necessary items, you should get an assortment of useful Pokémon. 

Ditto

The most important is Ditto. Ditto can breed with any Pokémon, of any sex, that can be bred. Sexless Pokémon can only be bred with Ditto. 

The most useful thing a Ditto can do, besides breeding sexless Pokémon, is pass down natures. Catch one Ditto of each of the 20 useful natures, which are:

• Adamant (+ATK, -SpA)
• Bold (+DEF, -ATK)
• Brave (+ATK, -SPE)
• Calm (+SpD, -ATK)
• Careful (+SpD, -SpA)
• Gentle (+SpD, -DEF)
• Hasty (+SPE, -DEF)
• Impish (+DEF, -SpA)
• Jolly (+SPE, -SpA)
• Lax (+DEF, -SpD)
• Lonely (+ATK, -DEF)
• Mild (+SpA, -DEF)
• Modest (+SpA, -ATK)
• Naive (+SPE, -SpD)
• Naughty (+ATK, -SpD)
• Quiet (+SpA, -SPE)
• Rash (+SpA, -SpD)
• Relaxed (+DEF, -SPE)
• Sassy (+SpD, -SPE)
• Timid (+SPE, -ATK)

Once you have these Dittos, you can pass down any desired nature by giving the elder Ditto an Everstone.

Catch your Dittos in the Friend Safari. The encounter rate there is 33%, and each will have at least two perfect 31-IVs. 

By placing a Magikarp that knows only Splash at the front of your party, you can force wild Ditto to transform into your Magikarp, which has the highest capture rating and only one useless move. Use a Repeat Ball on this Ditto to further increase the capture rating; since you already own a Magikarp, the ball's bonus will be applied.

Flame Body Fletchinder/Talonflame

The next most-useful Pokemon is Fletchinder or its evolution, Talonflame.

These Pokémon can both learn Fly, which is essential for travelling between the Daycare. the IV-Checker and more.

They also can have the ability Flame Body, which halves the number of egg cycles required to hatch eggs while the Flame Body Pokémon and the eggs are in the same party.

You can catch Fletchinder in the flying and fire Friend Safaris. Or, you can evolve it from Fletchling at level 17; Fletchling lives in Routes 2 and 3.

Synchronize Ralts

When a Ralts with the ability Synchronize is placed at the front of a party, encountered Pokémon have a 50% chance of copy Ralts's nature.

This is useful because you no longer must breed natures into Pokémon, since they can be captured with that nature. Also, legendary Pokémon, which can only be encountered once, can be caught with the desired nature half of the time.

However, the success rate of Everstone-holding Dittos passing down their nature is 100%, which makes it a more efficient method for everyday breeding.

Catcher

To catch wild Pokémon efficiently, two moves are almost essential: False Swipe, and a sleep-causing move. 

I recommend a Technician (Hidden Ability) Breloom for this role with at least max Attack, since it can learn False Swipe (TM 54) and Spore (level 45/40 Shroomish). 

Using these moves, Breloom can reduce a Pokémon's HP to 1, and then put it to sleep, which raises its capture chance more than any other method.

Ralts has many uses.

Tracer 

When searching for a Pokémon with a particular ability, especially for a female with a hidden ability, it is much more efficient to find out the ability of a wild Pokémon before you take the trouble to catch it.

Putting a Pokémon with the ability Trace in the first party spot will reveal the ability of any Pokémon you encounter before the battle begins. If you do not find what you are looking for, Trace will allow you to run from the battle on the first turn.

Frisker

Pumpkaboo is a easy-to-find Frisker

A Pokémon with the ability Frisk will reveal the held item of a wild Pokémon before the battle begins. This is useful if you are searching for a particular item, such as the Lucky Egg held by Chansey. Like Trace, you can run from battles on turn one if you do not find what you are looking for.

HM Slaves

When searching for wild Pokémon, you may need to use HMs and overworld moves, which are:

• Cut
• Flash
• Fly
• Rock Smash
• Strength
• Surf
• Sweet Scent
• Waterfall

The best two HM slaves are Bibarel and Tropius.

Surf, Waterfalls, Rock Smash, Cut

Fly, Sweet Scent, Flash, Strength

Hatching O-Power

The Level 3 Hatching O-Power halves the number of steps required to complete an egg cycle. This stacks with the Flame Body or Magma Armor ability. You can get the Hatching O-Power  only after all the other O-Powers are got. To do this in X&Y, speaker to Mr. Bonding in:

• Lumiose City/Route 5 Gatehouse (Attack Power and Defense Power)
• Hotel Camphier (Special Attack Power)
• Hotel Ambrette (Special Defense Power)
• Hotel Cyllage (Prize Money Power)
• Hotel Marine Snow (Speed Power)
• Shalour City Pokémon Center (Critical Power)
• Coumarine City Pokémon Center (Befriending Power)
• Hotel Richissime (Bargain Power)
• Laverre City Pokémon Center (Encounter Power)
• Dendemille Town Pokémon Center (Accuracy Power)
• Anistar Pokémon Center (Exp. Point Power)
• Couriway Hotel (Stealth Power)
• Snowbelle City Pokémon Center (PP Restoring Power)

And finally, in Café Introversion, when you have high style. 

To quickly increase your style, buy about 150 Premier Balls in Lumiose City, but only one per transaction. That is, make about 150 purchases, one after another, of one Premier Ball. Once the man in the Stone Emporium offers to sell a Mega Stone for $10,000, you have reached maximum style.

O-Powers recharge over time, but do so faster according to the number of real-world steps your game console counts in a day, about n-times for n-thousand steps, up to 4x. The game does not have to be running to count these steps.

Organizing Boxes

This is an optional step, but it will be useful. Breeding requires a lot of PC usage. You should dedicate boxes to:

• Organize Dittos, preferably named after their nature, and organized letterwise
• Organize Synchronize Ralts's, in the aforementioned manner
• Temporarily store Pokémon currently being bred, whose IVs have not been checked
• Store Super Studs
• Store useful Pokémon, like your Catcher, Flame Body, and Magikarp (these can be stored in one of the aforementioned boxes, such as the Ditto box)