Is it possible that schengen visa is denied due to fault in writing the application? I wrote 8 days in my itinerary while it was of 7 days. Kindly tell me what to do next as my visa got rejected.
Yes that is possible, it could be other reasons which you are not aware of and embassies/consulates do not share them usually. The best you can do is apply again and this time fill the application correctly and if the application contains a section about rejected visas do not forget to fill that as well.
P.S. EU embassies/consulates are straight forward, the best you can do always is to be honest and not to play smart. There are no known under the table methods to get around the rejection.