I don't know who told you that 了 means "a change in state". Don't learn Chinese from him. S/He is simply cheating you.

了 means something (usually the thing you're talking in the sentence) have been done; it is completed. It has nothing to do with a change of something. Forget about the change.

You speak because you want to convey something to your listener or reader. So you use 了 or not wholly for that purpose. Remember.

Specifically, when you say "他现在已经是一个有名的作家了。", you are convey the idea to your listener or reader that "他现在已经是一个有名的作家" is a fact. It is something that has already taken place and that has already done. He is not trying to be a famous writer, he is not in the process of being a famous writer, but he has already been a famous writer, for example, by already publishing a top-sell novel. That's what you want to convey by taking pains to speak this Chinese.

If you don't use "了", that mean your sentence does not care whether this thing has already done. Taking the previous sentence as an example, if you say "我在报纸上看到了一篇关于她的新闻", you are confirming to your listener that you have really read it. This reading has happened, and you can't disguise that you didn't. Also, that you have read her news means that the news is true, it is not something still in rumor. Maybe "我在报纸上看到了飞机失事的新闻" can explain this better. That's a confirmation that an airplane really crashed. 

But if you say "我在报纸上看到一篇关于她的新闻，" as in your question , you're not stressing that you have done a thing called reading her news. This sentence is acting only as a preamble. What is important is the next sentence "他现在已经是一个有名的作家了". So, you don't need to use 了 in "我在报纸上看到一篇关于她的新闻" to stress that you read a piece of news. What matters is the contents of the news, which you would say immediately, and confirm it is done and completed by using 了 in that sentence. 

To wrap up, remember that you are speaking to convey something, not just to pass an exam. Only by remembering this can you understand how to speak Chinese well (and all other foreign languages I think).