Here are just a few of my favorite spots for EV training certain stats and how to get there:
HP: Cowgirl Shelly
-She has 5 bidoofs so there is a chance for 50 possible HP EV's that can be easily gotten. To get to her fly to solaceon town and travel south for like 25 steps or so and you will see a cowgirl, this is her.
Attack: PI Carlos
-This is a great trainer to battle. Not only does he have three seaking, but he gives you about 6,500 pokedollars when you beat him. To get to him, fly to veilstone and go down and out to route 214. go right and then down and you will see a guy standing there with a guy walking up and down. Carlos is the guy who is standing there.
Speed: Collector Something
-Has three ponyta, he happens to be the guy walking up and down beside carlos... You could also find staravias in the wild.
Defense: Geodudes in Ruin Maniac's Cave
-Find them wild in the Ruin Maniac's Cave which is on the left side of Route 214.
Sp. Defense: ANNOYING
-Best would be tentacools in Pastoria. However you may find wingulls, run from them.
Sp. Attack: Collector at bottom of route 214, near Lake Front.
- Has three roselia, easy to beat and very rewarding.
I know there are also other decent spots, i just decided not to list them, hope this helps.
~CHICMHAR o(0.0)o