this/that: things
The ko/so/a/do row for things: near me, near you or just said, far or shared, and which.
kore
this (one)
これ
Points at a thing near you so you can ask about it or choose it before you know its name; it stands alone and never goes before a noun.
kore, ii ne.
This one's nice.
これ、いいね。
kore, ii desu ne.
This one's nice.
これ、いいですね。
Before a noun it becomes kono: kono hon, never kore hon.
sore
that (one); what you said
それ
Points at a thing near the listener, and even more often at what they just said, so it is the main way to react to an idea (sore hontou?, sore tte dou iu imi?).
sore, ii ne.
That's a good idea.
それ、いいね。
sore, ii desu ne.
That's a good idea.
それ、いいですね。
Use sore, not are, for something the other person just mentioned.
are
that (over there / we know)
あれ
Points at something away from both of you or something you both remember, and stands in for a word you can't recall (are, are da yo).
are, dou natta?
What happened with that thing?
あれ、どうなった？
are wa dou narimashita ka?
What happened with that thing?
あれはどうなりましたか？
Calling a person are sounds rude; say ano hito.
dore
which one (of several)
どれ
Asks which one out of three or more and takes ga, not wa (dore ga ii?); for a choice between two, use dotchi.
dore ga ii?
Which one do you want?
どれがいい？
dore ga ii desu ka?
Which one would you like?
どれがいいですか？
dore demo ii = any of them is fine.