Let your Pokémon hold Soothe Bell and train OR feed it Berries that lower its stats but makes it friendly- DON'T overdo it.
You can train them up at victory road or on the way to the survile area
Throw a masterball at it.
use wing attack [get starly and train to level 9 and it gets wing attack]
elite four again and again.worked for me
In route 1 thas the best way to train pokemon if your pokemon lvl `10
Give the Pokemon a soove bell and train it such as if its level 5 train it against Pokemon level 2,3, and 4
I would use rare candies. Or, train in Victory Road.
It's pretty obvious... EV train (I suggest EV Training in Defense)...
Train it.
Take them to the elite 4 and battle there.
The only way you can get an Elekid in Pokemon Platinum is by breeding an Electabuzz or Electivire.