We all know about writing and reading, but what do we mean by critical writing and reading ?

Writing and reading are not physical things but more so actions/concepts so we do not "know" them personally but instead we know "about" them; we have a general concept of them.

Also, in English we do not put spaces before punctuation marks.

If we write something, we have to think andbout how we feel about the object (subject).

I wanted to keep my correction as close to the original sentence as possible. However, for lack of redundancy, you could also say "we have to think about how the object (subject) makes us feel." This way the same word (about) is not repeated within the same sentence which is typically frowned upon.

Also, if you wanted to, you could combine this sentence and the one before it by turning the period after writing into a colon (:). Colons can be used to connect explanations or independent clauses when the second clause elaborates on the first clause. Although, your current sentence structure is perfectly fine :)

A good writer will always relates the its subject withto real life, give somes evidence about the subject, and writes in such a manner that everyone can easily understand.

"the" --> "its" because to show that the writer is in possession of the subject since it's what the writer has been tasked with writing about.

The second one is reading, which totally depends upon reader who reads it.

It's better to combine this sentence and the next one for the sake of clarity and flow.

It is totally depends upon the reader who reads it.

DIt depends on the reader's imagination and thinking process.

Since this is a new sentence it needs to have a subject, which is why I added the pronoun "It." It communicates that you are (still) referring to the subject you previously mentioned; reading.

We all know writing and reading, but what do we mean by critical writing and reading ?

If we write something, we have to think about and feel about the object (the subject).

Subject and object are different

A good writer always relates the subject with real life, giveing some evidence about the subject and writeing in such a manner that everyone can easily understand.

It is totally depends upon reader who reads it.

DIt depends on the reader's imagination and thinking process.

We all know about writing and reading, but what do we mean by critical writing and reading ?

If we write something, we have to think and feel about the object (subject).

A good writer always relateconnects the subject with real life, give some evidenceinformation about the subject and write in such a manner that everyone can easily understand.

Better to use "connects" here because it's about actively creating the relation.

"evidence" is more used for things that need proving, like arguments or lawsuits. It doesn't fit here so better to use more generic "information".

The second onething to understand is reading.

We're a few sentences away from "first" here, so it's not clear what "one" refer to.

It is totally dependsent upon reader who reads it.

DIt depends on the reader's imagination and thinking process.