I have to face many problems because of lack of content. How can I write unique article post about the same thing, about which I am writing for 3 or 4 months? How can I generate new unique content?
Broaden the subject of your posts a bit.
Try different angles.
Do a search for your subject and see what your competition writes about.
Follow the latest developments.
Search for the latest content that are trending in your niche then write about in your creation and make your own signature to make it fresh and interesting.
Is your topic evergreen or ever changing? For instance, social media is ever changing, what was new last month is old news this month. It’s important to keep an eye on trends, news, etc. I set up Google alerts for topics that I write about and watch the press release sites for news about a specific topic.
You can take a previously written article and update it, link back to it, and give people fresh news (if it’s an ever changing topic). If it’s ever green come back to say what’s working or what has changed in that topic since your last posting. Link back to old posts for those who are just now discovering the topic.
Use social media to garner interviews on the topic or put out a request for interview subjects, experts, etc. on the topic.
Explore sub-topics. Take for instance, Natural Living: explore the who, what, when, where, why and how of it. Expand on natural living products, why people choose to “live naturally” what does it mean to have a natural living lifestyle. What does it entail… topic ideas are endless. Do keyword searches to discover new keywords related to your topic… I could go on and on but you get the idea.
Try out some personal story or experiences and interviews for a change in the subject of your article content. This will help you to make people find more interesting to read your views and blog posts.
It is a good thing that you are focusing on the unique content. And if you want new isea then go to the Q/A sites or forums where you can get new idea for your post…And as guido2004 Sir said, you need to broaden your area of topic 
all the best happy blogging
I think same content issues comes when you copied your article and blog content from websites.So whenever google bots crawling it it creates problem.So you need to think ideas regarding your topic by reading latest updates and from different websites.
So this thing will increase your thinking power and will be able to write unique contents.
Check the prominent article directories and find out the content posted there that is related to your niche. Also, there are various online blogs, you can check for the latest topics from the blogs as well.
Copy content is the big problem and can affect your ranking in search engines hence you must have write unique and useful contents on your site. Or you can take help of content providers who provides services of unique unique contents.
It’s been over a month and the OP hasn’t returned, so I’m closing this thread.
Thanks to all who contributed.