This is a technical piece and you show fluency greater than that of most natives, so I will write at a high level while making corrections.  Very little of this contains hard corrections.  Mostly, I'm offering suggestions to communicate more effectively.

During the two-month internship with The Beijing News and Home Magazine, I was offered the opportunity to write different kinds of news reports.

Great!

With the guidance of my teacher, I gradually had a clear idea of the difference between news in newspaper and in TV and broadcast.

Good!  The use of "had" here is improper, but I very clearly understand what you are saying.  In conversation, I may not have noticed your use of the word.  A better thing to say would be "I gradually developed a clear idea" or "I gradually gained a clear idea."

And I also ___ have a comprehensive and profound understanding of news writing. 

It is not always incorrect to being a sentence with "and," but it is not recommended.  

I also feel like you're missing a verb in the first sentence.  You're not incorrect, but it flows better to say "I now have" or "I also now have."

This essay includes my experience and difficulties in the circle of house furnishing, for (...furnishing.  For example: ) example, how to have a general idea of this field and select the topic; how to prepare for the interview, how to communicate with the interviewee more effectively; how to attract more readers and deliver a message in news language; how to balance the my role of a journalist and an editor. This essay is the summary of my two-month internship.

Your communication here is not very effective, which makes it hard for me to give you an exact correction.  I can tell you that you should begin a new sentence with "For example:" rather than making it another clause of the same sentence.

I would suggest rewriting the first two sentences in a better way. The use of a "For example:" list disconnects the first sentence from the second.   I am a native speaker and I'm having an extremely hard time trying to tell you how to correct this, so don't feel like you failed.  The use of "how to" makes it seem more like advice than a tale of experiences and difficulties.

You did well in using semicolons to create your list.  It is very easy to read and well-organized.  You have one up on the vast majority of native speakers here.

The words I put in bold are extremely confusing.  I know what you are trying to say, but the use of words is very jumbled.   I think this is just an error in typing, not an error in fluency.  I may have even done the exact same thing in my corrections.

As a side note, the repetition of "this essay is ____" can come off as unprofessional and uneducated.  It is so difficult to use such a direct statement effectively that I can only remember doing this once in the last six years of essay writing.  It is, however, not incorrect.

I hope I could be more professional and have a better performance in the future.

This is a tricky correction to suggest.  It is not necessarily wrong, but you might get some funny looks if you speak this way.  The tense you are trying to use is ambiguous.  A more clear (and easier) way of saying this would be "I hope to be more professional in the future."

Overall, great work.  I would give this portion of your essay a B+ or (most likely) an A if I were grading it in an English class here in the States.  You used fitting vocabulary and employed effective variation in sentence length and stucture.