RMT - First attempt at anything competitive

Hi, I just joined this site in order to help better myself at competitive gameplay. I feel like this team has no synergy what-so-ever and like I simply based the entire team on sweeping.

Please be nice and critical at the same time, because I honestly have no idea what I'm doing when it comes to this type of gameplay. Any help at all is appreciated, thanks.

Scizor @ Life Orb
Trait: Technician
Evs: 32 HP / 252 Atk / 224 Spd
Adamant Nature
Swords Dance
Bullet Punch
Bug Bite
Brick Break / Superpower

Zapdos @ Life Orb
Trait: Pressure
Evs: 4 HP / 252 Spd / 252 SAtk
Timid Nature
Thunderbolt
Heat Wave
Hidden Power (Grass)
Roost

Suicune @ Life Orb
Trait: Pressure
Evs: 4 HP / 252 Spd / 252 SAtk
Modest/Timid Nature
Calm Mind
Hydro Pump
Ice Beam
Hidden Power (Electric)

Snorlax @ Leftovers
Trait: Thick Fat
Evs: 252 HP / 128 SDef / 128 Def
Sassy Nature
Curse
Fire Punch
Selfdestruct
Earthquake

Mewtwo @ Leftovers
Trait: Pressure
Evs: 4 HP / 252 SAtk / 252 Spd
Modest Nature
Thunderbolt
Ice Beam
Psybeam
Recover

Heatran @ Choice Scarf
Trait: Flash Fire
Evs: 4 Atk / 252 SAtk / 252 Spd
Naive Nature
Stealth Rock
Fire Blast
Earth Power
Hidden Power (Ice)

FYI: I know Mewtwo is considered Uber, he's filler because I don't know what I'm doing.

First of all, you need to know what Tier you are in. I suggest you read Smogon before you start creating a team.

Mewtwo is UBER, therefore BANNED from OU. If you know that, then you know that Mewtwo shouldn't be in your team in the first place, even if he is considered a filler.

Suicune, However, would make a good stall. Since you did not provide any descriptions as to why you have each pokemon on your team.

You could use a good physical wall. Perhaps you could replace Mewtwo with a Skarmory or a Foretress.

Snorlax wants a few more EVs in Def and maybe a few in Atk.