Grammar check
 

I wanted to know if this was the rigth usage of でも and if my senteces are good :p

猫（ねこ）　が　すき　でわ　でわません、でも　犬（ いぬ）　が　すきです。
(I don't like kats, but I like dogs.)

correct me if I'm wrong ^^
ども　ありがと in advance :p

You got a few things to work on. You can't use ません　in the middle of a sentance,

でわ is　では


so here is your first sentence.

猫が好きではないですけど、犬がすきです。　OR

猫が好きではないです。でも、犬が好きです。

I am not sure what your second sentence is saying.

just forget the 2e sentences -_-,... what's ですけど for a conjugation ( think this is the right english word :P ) or does that form connects two sentences?

です　＝　です。

けど is "but" and is the word used in the middle of a sentence.

thanks for the help :P I really was wondering how to connect 2 sentences ^^ domo arigato gozaimashita ^^

Okay, I noticed you deleted the second sentence, but I wanted to help, too, if I could.

For the differences between "wa" and "ga", normally the first is a topic marker, and the second is the subject (normally doing something) that precise the subject.

Example:

Kono hana wa tane ga haeteiru.

The seed (of this flower) is growing. or About this flower, the seed is growing. (this seems very unnatural, but it could be a translation to make the difference)

What is in the parentheses is what the topic marker here adds. Without it, the sentence is vague. It could be any flower's seed.

Tane ga haeteiru. The seed is growing. or The seeds are growing. or A seed is growing (Depends on context given)

See?

(Hope I didn't make any mistake, did I?)

This is exactly why people shouldn't learn Japanese using romaji. I'm not really calling you out on anything, but just using it as an example (specifically the usage of spaces and writing the kana わ instead of は).

Thanks for the help ^^,
@Hatredcopter sorry for the mispelling -_- I type it as i speak XD it was a stupid mistake :P But when I write I write it without a fail.
@Seiryuu I know it now ^^, learned it in the past week when Ihad vacation:P

Now there some more sentences where I want to see f I could have some backfeed bout them.

月の青い、凄いです。あなとは死なければならないか？ はい。でも、とにかこ、あなとを守るつみりです。それ からあなとを愛ですつもりです。さよなら。待て！千代 に待つつもりです。

I think there're a few mistakes but I want to know if I got it right.
And the last question ^^ I'm a bit a pain in the butt :P
what's the difference between 食べません and 食べない. I know they both are negatives and that you can change nai into an form of the adjectives. but whats the difference?

月の青い、凄いです。 --> 月の青さは凄いです。
adjectives in -i take -sa when are used as nouns. Use a "は" to mark the subject of the sentence.

あなとは死なければならないか？ --> あなたは死ななければならないのか？
"you" is written "あなた", not あなと.
The "have to" form is used with the same form you use to make the plain negative form (in this case, "shinu" becomes "shina-"), thus 死ななければならない, not 死なければならない.
I added a "no" just because it sounds better. Japanese people use a no/nani at the end of sentences where tell somebody something new. I've been told this rule, but actually never understood it fully, I just use it when it sounds better.

とにかこ、あなとを守るつみりです --> とにかくあなたを守るつもりです。
"とにかこ"? I suppose you meant とにかく, "anyway". And again, it's "あなた".

それ からあなとを愛ですつもりです。 --> それから、あなたを愛するつもりです。
The verb "to love" is 愛する, so it goes like 愛するつもりだ.

さよなら。 --> さようなら。　
You forgot a う. Sa-yo-u-na-ra, not sa-yo-na-ra.

待て！--> 待って！
The te-form of verbs ending in "tsu" is "-tte", not "te".

さよなら。待て！千代 に待つつもりです。 --> 千代 に待っているつもりです。
I think your sentence is probably correct, but I think that since you're referring to a continuative situation, it's better to use the "-te iru" form.

The first is a negative in the polite form, the second in the plain form. The plain form is used among familiars, (friends, family...), the polite form is used with superiors and unknown people, but there isn't any difference between them (except for the level of politeness).