Gyarados@Leftovers
Adamant, Intimidate
156 Hp, 108 Atk, 100 Def, 144 Spe

- Dragon Dance
- Ice Fang
- Waterfall
- Taunt


Alakazam@Life Orb
Timid, Synchronize
252 SpA, 252 Spe, 4 SpD

- Shadow Ball
- Psychic
- Grass Knot
- Hidden Power (Fire)


Umbreon@Leftovers
Sassy, Synchronize
252 Hp, 200 Atk, 56 Spd

- Curse
- Payback
- Wish
- Yawn


Electrivire@Choice Scarf
Adamant, Motor Drive
252 Atk, 252 Spe, 4 Hp

- Cross Chop
- Fire Punch
- Thunderpunch
- Earthquake


Shaymin-s@Leftovers
Timid, Serene Grace
252 SpA, 252 Spe, 4 Hp

- Air Slash
- Seed Flare
- Substitute
- Earth Power


Blissey@Leftovers
Bold, Natural Cure
252 SpD, 248 Def, 4 Spe

- Seismic Toss
- Stealth Rock
- Softboiled
- Toxic / Thunderwave

Any reason in particular you're running Fire Punch on Electivire instead of Ice Punch? The latter gives Electivire the best type coverage in the entire game, you know.

It would be nice if you included explanations for why you have the Pokes on your team.

Gyardos is fine, gets beaten by lead Gengars and such...have fun with that.

Hidden Power Fire on Alakazam does not do much coverage wise. You'd be better off with Ice or Focus Blast if all you're trying to hit is Steel type Pokemon. Other than that it is fine.

Umbreon is dead weight. Get rid of it. Without Toxic it doesn't do anything from what I see.

Ice Punch over Fire Punch on Electrivire.

I don't really know why you have Sub on Shaymin when you don't have Leech Seed...but that's just me. Either add Leech Seed or get rid of sub and go all offensive.

Blissey gets walled by Gengar.

From the looks of your team, you're gonna have serious problems with other Shaymin, Gengar, ScarfCross, etc.

I kinda don't feel like going through more changes...you can do that yourself. Besides it'll help you make teams better if you do it yourself :)