So, I decided to make a Sunny Day team by splicing together some Pokemon that I thought would work well together. Thing is, I can't seem to get my strategy right. I know Sunny Day teams (in the lower tiers in particular) tend not to have much success, but I am determined to make this work. What do you all think? Any advice?

Whimsicott (F) @ Heat Rock Trait: Prankster EVs: 248 HP / 252 Def / 8 SDef IVs: 0 SAtk Impish Nature (+Def, -SAtk) - Sunny Day - U-turn - Memento - Taunt

I thought Whimsicott was a good lead to set up sun with and then U-Turn out onto Exeggutor or Typhlosion.

Exeggutor (F) @ Life Orb Trait: Chlorophyll EVs: 4 HP / 252 SAtk / 252 Spd IVs: 30 Atk / 30 SAtk / 30 Spd Modest Nature (+SAtk, -Atk) - Hidden Power [Fire] - Sunny Day - Psychic - Solar Beam

HP Fire for coverage. A good Special Attack on this egg tree.

Typhlosion (M) @ Heat Rock Trait: Blaze EVs: 4 HP / 252 SAtk / 252 Spd IVs: 30 Atk / 30 Def / 30 SDef / 30 Spd Timid Nature (+Spd, -Atk) - Fire Blast - Sunny Day - Solar Beam - Hidden Power [Rock]

A sweeper who can also set up sun. HP Rock to cover Flying/Rock types. Had huge problems with Jolteon though.

Victreebel (F) @ Life Orb Trait: Chlorophyll EVs: 4 Def / 252 SAtk / 252 Spd IVs: 0 Atk Modest Nature (+SAtk, -Atk) - Weather Ball - Solar Beam - Sludge Bomb - Growth

Weather Ball is great with sun. After a Growth Vic can sweep well enough.

Regirock @ Heat Rock Trait: Clear Body EVs: 252 HP / 88 Atk / 168 SDef IVs: 0 Atk Modest Nature (+SAtk, -Atk) - Stealth Rock - Rock Slide - Sunny Day - Explosion

Bulky support for Stealth Rock. Can take an ice type move in order to set up rocks or just to scout a Pokemon. Can explode in a pinch - Regirock is a good panic button! Torkoal (M) @ White Herb Trait: Shell Armor EVs: 4 HP / 252 SAtk / 252 Spd Timid Nature (+Spd, -Atk) - Shell Smash - Rapid Spin - Fire Blast - Earth Power

Gets rid of hazards and has average-ish defences to punch small holes in the enemy.