Hello,
Here's my team. I'm relatively new to this, so there's probably holes, so suggestions please.
Obamasnow@Focus Sash
252HP/ 152Def/ 104Sp. Atk
Neutral Nature
-Leech Seed
-Protect
-Ice Shard
-Blizzard
An obvious choice for a hail team. Starts the hail and can actual get a kill a good amount of the time. Leech Seed and Protect for stall with hail, blizzard for STAB, and Ice shard for that extra hit before he goes down. The only special attacks people use on him generally are fire, so I just focused on defense EVs, and then focus sash to survive one fire move and get leech seed on them.
Forretress@Leftovers
252HP/ 220Def/ 36Atk
Relaxed Nature
-Stealth Rock
-Toxic Spikes
-Rapid Spin
-Explosion
This is one of my spinners. His main function is to lay down Stealth Rock and Toxic Spikes. He's also good for taking guys that have set up with Explosion. I only switch him in to Physical attackers, so I focused on defense. I gave him leftovers to cancel out the hail.
Froslass@ Leftovers
252Spd/ 156HP/ 100Sp. Atk
Timid Nature
-Confuse Ray
-Thunder Wave
-Substitute
-Blizzard
This thing can really do damage. If I get then paralyzed and confused, combined with Snow Cloak, she only gets hit 30% of the time. I don't like running Toxic over thunder wave because her defense isn't too great, and getting hit more is bad. It also makes her faster than Gengar, who's a common switch in. Substitute I use after they're confused and paralyzed. Blizzard is for a strong STAB to do decent damage with her poor Special Attack. She's also used as a spin blocker.
Walrien@Leftovers
252HP/ 48Spd/ 160 Sp. Def/ 52 Sp. Atk
Bold Nature
Ice Body
-Protect
-Substitute
-Toxic
-Surf
I love this guy. If he's faster than you, he will beat you if you aren't an ice type and he's at full health. he regains 12% every turn from Leftovers and Ice Body combined with Toxic and hail is great. He benefits from Toxic Spikes a lot because he doesn't have to use a move on toxic and the can't substitute away from it.I like Surf over Blizzard to help the teams fire weakness, and so he can hit Steel types harder because they aren't affected by Toxic.
Starmie@Leftovers
252 Spd/ 252 Sp. Atk/ 4HP
Timid Nature
Nature Cure
-Surf
-Psychic
-Blizzard
-Rapid Spin
This is my second spinner. I like to have 2 since my team has big weakness to stealth rock. Also, Toxic spikes are a big threat to Froslass and Walrien, because if they're poisoned, then I'm stalling myself. Starmie really helps my team's weakness to fire and fighting. I run surf over Hydro Pump because I've always preffered accuracy over power. I like Timid over Modest because I was tired of being outran by Infernapes and Gengars. Leftovers to cancel out the hail.
Weavile@Focus Sash
252 Atk/ 252Spd/ 4 HP
Jolly Nature
-Ice Punch
-Night Slash
-Ice Shard
-Low Kick
Good revenge killer. He outruns almost everything and still has great power. Ice shard because I always like having a priority attack on one of my dudes(Abomasnow doesn't count cause he's already dead at the beginning of the battle). Ice Punch and Night Slash for STAB, and Low kick to hurt or faint the Tyranitars and Heatrans they always switch into. I like having someone with a Focus sash to take out guys that have set up, and I have two spinners, so it's rarely wasted by Stealth Rock. Though he doesn't benefit too much from the hail, him being an Ice type is definitely helpful.
Common treats-
Tyranatar/Hippodon(obviously)
Machamp
Infernape
Jirachi
Lucario
Here's my team. I'm relatively new to this, so there's probably holes, so suggestions please.

Obamasnow@Focus Sash
252HP/ 152Def/ 104Sp. Atk
Neutral Nature
-Leech Seed
-Protect
-Ice Shard
-Blizzard
An obvious choice for a hail team. Starts the hail and can actual get a kill a good amount of the time. Leech Seed and Protect for stall with hail, blizzard for STAB, and Ice shard for that extra hit before he goes down. The only special attacks people use on him generally are fire, so I just focused on defense EVs, and then focus sash to survive one fire move and get leech seed on them.

Forretress@Leftovers
252HP/ 220Def/ 36Atk
Relaxed Nature
-Stealth Rock
-Toxic Spikes
-Rapid Spin
-Explosion
This is one of my spinners. His main function is to lay down Stealth Rock and Toxic Spikes. He's also good for taking guys that have set up with Explosion. I only switch him in to Physical attackers, so I focused on defense. I gave him leftovers to cancel out the hail.

Froslass@ Leftovers
252Spd/ 156HP/ 100Sp. Atk
Timid Nature
-Confuse Ray
-Thunder Wave
-Substitute
-Blizzard
This thing can really do damage. If I get then paralyzed and confused, combined with Snow Cloak, she only gets hit 30% of the time. I don't like running Toxic over thunder wave because her defense isn't too great, and getting hit more is bad. It also makes her faster than Gengar, who's a common switch in. Substitute I use after they're confused and paralyzed. Blizzard is for a strong STAB to do decent damage with her poor Special Attack. She's also used as a spin blocker.
Walrien@Leftovers
252HP/ 48Spd/ 160 Sp. Def/ 52 Sp. Atk
Bold Nature
Ice Body
-Protect
-Substitute
-Toxic
-Surf
I love this guy. If he's faster than you, he will beat you if you aren't an ice type and he's at full health. he regains 12% every turn from Leftovers and Ice Body combined with Toxic and hail is great. He benefits from Toxic Spikes a lot because he doesn't have to use a move on toxic and the can't substitute away from it.I like Surf over Blizzard to help the teams fire weakness, and so he can hit Steel types harder because they aren't affected by Toxic.

Starmie@Leftovers
252 Spd/ 252 Sp. Atk/ 4HP
Timid Nature
Nature Cure
-Surf
-Psychic
-Blizzard
-Rapid Spin
This is my second spinner. I like to have 2 since my team has big weakness to stealth rock. Also, Toxic spikes are a big threat to Froslass and Walrien, because if they're poisoned, then I'm stalling myself. Starmie really helps my team's weakness to fire and fighting. I run surf over Hydro Pump because I've always preffered accuracy over power. I like Timid over Modest because I was tired of being outran by Infernapes and Gengars. Leftovers to cancel out the hail.
Weavile@Focus Sash
252 Atk/ 252Spd/ 4 HP
Jolly Nature
-Ice Punch
-Night Slash
-Ice Shard
-Low Kick
Good revenge killer. He outruns almost everything and still has great power. Ice shard because I always like having a priority attack on one of my dudes(Abomasnow doesn't count cause he's already dead at the beginning of the battle). Ice Punch and Night Slash for STAB, and Low kick to hurt or faint the Tyranitars and Heatrans they always switch into. I like having someone with a Focus sash to take out guys that have set up, and I have two spinners, so it's rarely wasted by Stealth Rock. Though he doesn't benefit too much from the hail, him being an Ice type is definitely helpful.
Common treats-
Tyranatar/Hippodon(obviously)
Machamp
Infernape
Jirachi
Lucario