THis next part is probably the most important but only one you can find out for yourself (as corny as it sounds). YOu could get a really good team off someone but if it doesn't fit your playing style then it won't go that well. Personally I like more balanced fast paced teams or hyper offensive. You can only tell what style best suits you after a fair amount of battling with different types of teams. There are also styles of battling that just don't work for a certian person, I know i can't use a full stall team *shudders*.

Styles of teams:

balanced:

Balanced style is exactly that. Not to much stall (generally a special wall + def wall). Not to much offence( generally 2 fast (atk+spA), 2 bulky(atk+spA)). The most common style and it is very flexible and more like the gray area between stall and hyper offence then anything eles.

Here is a nice looking team Found on smogon RMT that fits balanced quite well and is not to bad.

Thundurus@Focus Sash
Nature: Timid
Ability: Prankster
Evs: 252 SpA, 252 Spd, 4 HP
Moves:
Thunderbolt
Hidden Power (Ice)
Volt Switch
Taunt

Reuniclus@Life Orb
Nature: Relaxed
Ability: Magic Guard
Evs: 252 HP, 252 Def, 4 SpD
Moves:
Psychic
Focus Blast
Calm Mind
Recover

Dragonite@ Choice Band
Nature: Adamant
Ability: MultiScale
Evs: 4 HP, 252 Atk, 252 Spd
Moves:
Outrage
Earthquake
Fire Punch
Extremespeed

Jirachi@ Leftovers
Nature: Careful
Evs: 240 HP, 20 Def, 216 SpD, 32 Spd
Moves:
Iron Head
Thunder Wave
Wish
U-turn

Vaporeon@ Leftovers
Nature: Bold
Ability: Water Absorb
Evs: 188 Hp, 252 Def, 56 SpA, 12 Spd
Moves:
Scald
Wish
Roar
Protect

Donphan@ Leftovers
Nature: Adamant
Ability: Sturdy
Evs: 252 HP, 252 Atk, 4 Def
Moves:
Earthquake
Ice Shard
Rapid Spin
Stealth Rock

Hyper offensive:
There are lots of differnet ways hyper offensive can work tho most of the time it is chaos and has no defensive synergy but lots of offensive synergy. Hyper offensive loves entry hazzards as they force switches and can get that extra damage needed for the kill. Screens are also a big thing that hyper ofence loves as they can set up and take a minimal amount of damage. Deoxys Speed is its best friend as it can get up rocks and screens quite reliably

This is a team I have being using and as hyper offensive goes this is the extreme and it has goten me tons of wins and is really good. It probably is the most chaotic team i have ever seen:

Deoxys-S @ Light Clay
Trait: Pressure
EVs: 252 HP / 4 SDef / 252 Spd
Timid Nature (+Spd, -Atk)
- Light Screen
- Reflect
- Magic Coat
- Stealth Rock

Haxorus (F) @ Life Orb
Trait: Mold Breaker
EVs: 4 HP / 252 Atk / 252 Spd
Adamant Nature (+Atk, -SAtk)
- Dragon Dance
- Outrage
- Earthquake
- Brick Break

Scizor (F) @ Life Orb
Trait: Technician
EVs: 4 HP / 252 Atk / 252 Spd
Adamant Nature (+Atk, -SAtk)
- Swords Dance
- Bug Bite
- Bullet Punch
- Brick Break

Salamence (F) @ Life Orb
Trait: Intimidate
EVs: 232 Atk / 24 SAtk / 252 Spd
Naive Nature (+Spd, -SDef)
- Dragon Dance
- Outrage
- Earthquake
- Fire Blast

Garchomp (F) @ Haban Berry
Trait: Sand Veil
EVs: 4 HP / 252 Atk / 252 Spd
Jolly Nature (+Spd, -SAtk)
- Swords Dance
- Outrage
- Earthquake
- Fire Fang

Terrakion @ Air Balloon
Trait: Justified
EVs: 252 Atk / 4 SDef / 252 Spd
Adamant Nature (+Atk, -SAtk)
- Rock Polish
- Swords Dance
- Close Combat
- Stone Edge

Stall:
The most imfamous of all styles (ss closly follows). They set up hazzards and roar you away all day *shudders*. Protect and toxic. Stall has a new friend called FerroCent probably worse than SkarmBlis. Tho nearly everyone is guilty of using ferrothorn and/or jellicent *raises hand*.

Here is another team I found on smogon RMT I don't think it is as good as the other one but it is a good enougth example:

Hippo
Trait: Sand Stream
EVs: 252 HP / 168 Def / 80 SDef / 8 Spd
Impish Nature (+Def, -SAtk)
- Stealth Rock
- Slack Off
- Ice Fang
- Earthquake

Latias
@ Leftovers
Trait: Levitate
EVs: 252 HP / 228 Def / 16 SDef / 12 Spd
Bold Nature (+Def, -Atk)
- Wish
- Roar
- Protect
- Draco Meteor

scizor
@ Choice Band
Trait: Technician
EVs: 252 HP / 252 Atk / 4 Spd
Adamant Nature (+Atk, -SAtk)
- Bullet Punch
- U-turn
- Pursuit
- Superpower

Jellicent
@ Leftovers
Trait: Water Absorb
EVs: 252 HP / 96 Def / 144 SDef / 16 Spd
Calm Nature (+SDef, -Atk)
- Scald
- Recover
- Shadow Ball
- Toxic

Ferrothorn
@ Leftovers
Trait: Iron Barbs
EVs: 252 HP / 4 Def / 252 SDef
Relaxed Nature (+Def, -Spd)
- Spikes
- Leech Seed
- Gyro Ball
- Power Whip

Heatran
@ Leftovers
Trait: Flash Fire
EVs: 244 HP / 36 SAtk / 12 SDef / 216 Spd
Calm Nature (+SDef, -Atk)
- Torment
- Substitute
- Protect
- Lava Plume

There is an extra bonus sub style called weather. It comes in stall, blanenced and hyper offence and can be a real pain. There is SandStorm, Rain, Sun, Hail in decresing order of popularity and usage. It is a huge part of the meta game and has been made a whole lot better thanks to: drizzle toad, drought tails, Landorus and last but most deffinatly not least Exadrill (fun fact: Exadrill is only about 2 feet tall O.o). It is not as bad as when the game first came out and Doyruzuu counter was almost made an offical role. Weather usualy consists of weather set up, and about 2-3 abusers. I ran an unconventional SS team back in 4th gen before it was popular and I converted it to 5th gen and it does amazing (no exadrill). I think I may be geting to much off topic so it may be time to rap it up (tho I know I missed Trick room which is the same as weather except more than one set up poke).