IV's aren't something you can just "get". They are completely random, and no amount if Soft-Resetting or any other legitimate method will get you guaranteed results.
However, all Legendary Pokemon have maximum IV's (31) in three of their stats (again, I think the specific stats affected is random as well, but I could be wrong).
Other times, people just get really, really lucky. Other methods include "cloning" of Pokemon with good IV's (like Smogon's Penta-flawless give-aways, which basically consist of cloning a Pokemon that was specifically bred for good IV's).
So, sorry, but apart from certain events, like give-aways, or illegitimate means (like Pokegen), I don't think you can guarantee good IV's in the stats of the Pokemon you want.
The hardcore ones, well, they spends lots of time for the level of perfection, but that too has no guarantee to work.
>Every Pokémon has two hidden numbers in their data, called Individual Value and Personality Value. They are random for every wild Pokémon you encounter and you can't change them. They determine a whole range of attributes including stats, gender, ability, nature and characteristics.
--The Database on IV's