A lot of it is experimentation to see what works. If you're a newcomer, it's best to just slap together a team, play a few games, and figure out what isn't working.
With regards to your first question, that sounds a lot like a stall team, winning through residual damage with entry hazards, possibly weather, and a few light hits and status effects.
Your second question is variation of a balance team, seeking to counter what the other team tries to do as you set up an opening for your sweeper to do damage. Team synergy is incredibly important and really, the only answer to that is experience. Competitive pokemon is a complex thing.
Here's a stupid of question of mine: Does the Regenerator ability trigger its heal if the pokemon in question is phased though Whirlwind/Roar/Overhead Throw/Dragon Tail?
With regards to your first question, that sounds a lot like a stall team, winning through residual damage with entry hazards, possibly weather, and a few light hits and status effects.
Your second question is variation of a balance team, seeking to counter what the other team tries to do as you set up an opening for your sweeper to do damage. Team synergy is incredibly important and really, the only answer to that is experience. Competitive pokemon is a complex thing.
Here's a stupid of question of mine: Does the Regenerator ability trigger its heal if the pokemon in question is phased though Whirlwind/Roar/Overhead Throw/Dragon Tail?