Based on the OP's whereabouts, here's the way I would try to make it clear:

вы/Вы = you (polite form); you (multiple people)
It's akin to the German word for Sie/Ihr;
The Turkish way of "siz"(ler)

How are you doing, sir? (you're talking to an official...or someone who's not your close friend) => ВЫ
Did you guys go to the cinema? (go figure...you guys...a multitude of ppl) => ВЫ
Did you clean your room? (talking to your roommates, kids, or whoever is being told in this case - the person is close to you) => ТЫ
You're walking down the street and see your parents => ВЫ (multitude). You talk to one of them => ТЫ
You're walking down the street and see two board members of your company. => ВЫ (multitude). You talk to one of them => ВЫ (unless that person is a good friend of yours).

I agree on what others have said about ЧТО. Also, based on what my Russian prof. used to do (or rather warn): Do not try to mix it up with СТО.
(in case you speak another Slavic language...)