If you over optimize for example your content is stuffed with keywords your site's position on Google search will start going down.
Hi, I think if site affected try to optimize site content which is more important factor in search engine.
You may know about your site affection after using Google Analytics and checking all keywords position. If your keyword goes down on search engine and there is no any traffic on your site (you may know about traffic from Google Analytics that show complete graph of your site) it means your site is affected over optimization. But its important to check your site progress day-to-day.
if i submit every month 15 article and 15 blog is that ok or it will affected for over optimization ?
Firstly, you can come to know by seeing the change in Keywords Positions and then if you see the traffic in Google Analytics, you can identify and over come it where it went wrong in the website.
Check your visibility 1. How many indexed pages before and after? 2. How many queries that have referred you traffic? 3. Is your traffic from organic have reduce from Analytics? Then, you will get the answer for this question. I assume you must have Google Webmaster Tools and Google Analytics account.... if not, please get one...
If you are using a Wordpress CMS then I suggest u get an on page seo plugin like seopressor.. then try to score around 90% on seo pressor...dont go higher than that...