Japanese sentence structure?

Kore wa watashi no uchi no naka ni iru inu desu. (this is a pretty difficult grammar to understand as a complete beginner, but this is a relative clause. You'll cover this when you learn more of the basics)
これはわたしのうちのなかにいるいぬです。

Watashi no inu wa watashi no hoteru de inku wo tabemasu
わたしのいぬはわたしのホテルでインクをたべます

anata no kireina inu wa doko desu ka
あなたのきれないないぬはどこですか。

I don't want to confuse you too much, as it seems you're just starting out.

Firstly, Japanese has three different 'alphabets'. Hiragana, katakana, and kanji.

You used all hiragana, but a couple of words should be in katakana. Katakana is used for words borrowed from foreign languages. The words in your sentences would be 'hoteru' and 'inku'.
We use characters called kanji in place of hiragana, but never katakana. Kanji does not apply to every word, but applies to many, and has many readings. Kanji would take years to master, so it's best to look online or a buy a book and start from the basic, common kanji. If you don't know the kanji for a certain word, you always have hiragana to fall back on.

I'd look at online lessons. As a student of Japanese myself, I understand how much you want to be able to compose longer sentences! :P But you'll need a lot of patience and hard work to slowly build up to this point.

It's tricky to define word order, as it's not always set in stone. However this is a typical sentence structure.

Watashi no inu wa kesa neko to uchi de ringo wo zenbu tabemashita.

Subject Time With who Location object counter (1 apple, 2 apples, etc.) verb

This morning, my dog ate all the apples in the house with the cat.

kesa = this morning
neko to = with the cat
uchi de = in the house
ringo wo = apples
zenbu = all
tabemashita = ate

It's also a good idea to learn about particles, a very key part of Japanese (wa, ga, to, wo, ni, de, no, etc.) You'll learn about these gradually as you start to learn to build up your sentences.

I hope this was of some use, and best of luck with your studies!

*EDIT* Again, this is why studying particles is really important ^_^ 'de' and 'ni' are not interchangeable. When we talk about a subject carrying out an action in a location, we use 'de'.

We use 'ni' to describe something existing in a location; not carrying out an action.

For example:

ringo ga hako no naka ni arimasu - The apple is in the box
Takusan hito wa heya ni imasu - There are lots of people in the room

watashi wa kouen de asobu no ga suki desu - I like playing in the park
toshokan de iroiro na hon ga yomemasu - You can read various books in the library

Your sentence orders are pretty off. ^^;

1. これは私の家にいる犬です。
kore wa watashi no ie ni iru inu desu. Literally "This is the dog that that exists in my house."

2. ホテルで私の犬はインクを食べます。
hoteru de watashi no inu wa inku wo tabemasu. You can also change "hoteru de" to "hoteru ni"

3. あなたのきれいな犬はどこですか？
anata no kireina inu wa doko desu ka? The subject here is "your beautiful dog", so it would be the first part of the sentence.