My 2 pennies:
kanojo wa watashino kuruma ga suki.
かのじょ は わたしの くるま が すき。
Intended to mean "She likes my car".
This one is fine
watashi wa neko to inu ga kashikoi o desu.
わたし は ねこ と いぬ が かしこい お です。
Intended to mean "Both my cat and dog are smart" .. Not the exact words but sentence should mean the same thing.
I think it should be
いぬ と ねこ は
the の shows that the cat and dog belong to you
(or が?) show that it's the animals that are smart.
nani o aritsuita?
なに を ありついた？
Intended to mean "What did you get?"
I don't think this ありつぎ is very common...
the most common way to say this would be:
なに を もらいました か
with 'もらう' , to receive.
you need the か particle to show the sentence is a question, although in speech, intonation might be enough.
(Not with polite language, I think)
Actually the whole giving and receiving bit is very complicated in Japanese. Lots of different words for different occasions...
dare ga onushi desu?
だれ が おぬし です？
Intended to mean "Who are you?"
御主; お主 【おぬし】 (pn,adj-no) (arch) you (when referring to one's equals or inferiors)
According to Jim Breen this おぬし is very archaic.
asking someone who they are is a very delicate matter in Japanese, I think.
Maybe you should ask: 'what is your name?'
あなた の なまえ は なに です か。
But I doubt anyone in Japan would ask it like this
still, all in all not too bad for a first try!
Darn, this is the first time I noticed the 'notify me when a reply is posted' box