Ok for example give your Milotic 10 zinc's and 10 Iron's then give it pokerus. Make the Milotic hold the macho brace and then battle and KO 38 swaddle or venipede. Have Milotic no 1 in your party and if it's too weak switch it with a stronger pokemon to KO the pokemon. Now battle 38 Frillish. Your pokemon will be fully EV trained in Defense and Special Defense. After that you can fill in the four extra EV's in any other stat the quickest way to do this is using the wings found on Driftveil bridge.
Hopefully that helped.
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