I know how to evolve this pokemon, but I am going to wait a bit first, so here is my Seadra:
Ability: Poison Point- Stalling my enemy
Item: Dragon Fang- Power up on dragon moves
Surf- Power, Accuracy, Stab, movement on water.
Dragon Pulse- Power, Accuracy, Dragon Fang.
Double Team- My Seadra's poor special defense might not be a problem.
Protect- Stalling with Poison Point.