です

です is the general ending of affirmative sentences. In Japanese,

you can say

• 私は田中です
• 私は田中

The meaning of these two sentences is the same, but the degree of politeness is different.

Adding "です" is the most common practice, and it is also a more formal way of speaking.

じゃ

• じゃ＝では≈so

じゃ is the colloquial form of では. Similarly, saying では is more polite and formal than saying じゃ.

なの

Generally only children can use it.

What I mean is that children, especially those around 10 years old, like to add the word "なの" at the end of the sentence. Normal adult Japanese don't speak that way.

In addition, なの has an emphasized tone in it.

なの has no meaning. What you need to pay attention to is what is in front of なの. This part is what she/he wants to emphasize.

In Anime, なの's way of speaking generally makes this character feel cute.

だ

だ means that things have been done, for example:

• 宴の始まりだ

Google Translate: It's the beginning of the feast.

But if you understand this sentence correctly, it should mean that the current situation is the beginning of the feast.

In other words, the feast has already begun and is now in a state of beginning.

宴の始まり does not mean done, but just means a state.

"だ" there is also a sense of emphasis in this sentence.

Although I have given an example, I still recommend that you study it systematically. 

To explain accurately, だ is actually short for です. Here are a few examples:

• ですーだ
• でしたーだった
• ではありませんーではない
• ではありませんでしたーではなかった

以上です。

As before, simplified Japanese sentences mean impoliteness. I strongly recommend that you do not use the simplified version unless you have a close relationship with the person you are communicating with.

さ

さ at the end of a sentence, it generally means that the speaker thinks what he said is objective.

For example:

• これは，日本語の雑誌さ。 それは君の間違いさ。

This involves the issue of Japanese culture. Japanese people generally do not directly express their subjective opinions. They will certainly express in an objective form to achieve the purpose of respecting others or avoiding conflict.

For example, I know you did something wrong, but I cannot express my subjective view. I must add a さ to show that it is objective.

ですね

ですね is a very common end of a sentence that is eager for others' approval.

ですよ

ですよ at the end of a sentence means to tell others what they don't know.

ですよね

If you just say ですよね, it means that you agree with the person you just talked to.

For example, someone said:

• アメリカの選挙には不正行為があると思います。

You can just say: ですよね to show that you agree with this person's point of view.

The ですよね here means: "That's right. I also think there is cheating in this US election."

More: 

[1] More about YAKUWARIGO（関西人、老人、男の子、武士、田舎の人、お嬢様 、etc.）

[2] [JLPT N1 Test] The Japanese-Language Proficiency Test N1 Level Questions and Answers