The placement of nicht is something that you just have to get a sense for.
Why "She does not like dresses" is not correct???plural nouns in english dont' need the article...or yes???
The "sie" that means "you" will always be capitalized, like "I" in English. There's no way to tell it, when spoken, though, so you would go on context.
Remember the conjugation of the verb, most of the time it would say you the pronoun. Not always, sometimes it is inferred from the context.
I think, because of this (quoted from DL's tips and notes): ...Finally, "nicht" also tends to come at the end of sentences (after direct objects like "mir" = "me,"... I think in this sentence "die Kleider" is a direct object