Ground:
- 30/30/30/31/30/30
- 31/31/31/30/30/31
- 30/31/31/30/30/31
- 31/30/31/30/30/31
So lets say you choose 31/31/31/30/30/31
That means you need an Eevee with 30 IV's in Sp.Atk and Sp.Def.
Step1- Go to the Friend Safari in X/Y and catch Dittos like crazy. You need 2 Dittos. One with 30 Sp.Atk and another with 30 Sp.Def.
You can tell if a Ditto has 30 or 31 if the stat is as followed:
no nature boost: 42
Any other stat with negative nature: 37
Any other stat with positive nature: 46
In order to make sure it is 30 and not 31, simply go to the judge.
Step2- Take an Eevee (no matter which), and breed it with one of the Dittos. The easiest way to fast inherent the 30 IV from the first Ditto is by giving it the fitting Power Item, but you can simply breed like crazy with Destiny Bond. Take the Eevee babies to the Battle Institute in Lumiose City, (save beforehand) to boost any Eevee you want to check to level 50, where it is easier for IV calculators to check. Use this method along with the judge until you get an Eevee with 30 IV in Sp.Atk/Sp.Def. (x/x/x/30/x/x)
Step3- Now take the x/x/x/30/x/x Eevee and breed it with the other Ditto. Once again you need to breed like crazy until you get Eevee with x/x/x/30/30/x IV's
Step4- Now take a Modest perfect IV Eevee, breed it like crazy with the x/x/x/30/30/x Eevee, until you get the dream Modest Eevee with 31/x/31/30/30/31 IV's. (Don't forget to add the Everstone here on the Modest Eevee).
This process is long and should only be made if you really have a lot of time to kill.
The easier way is to find someone to trade with. If you don't mind using a hacked Ditto, the best thing a HP breeder can have is a hacked Ditto with 30 IV's in all the stats.