How to Overcome from Google Penalty?

I hope this is the best section to ask my question.

My site was doing well in Google and had good amount of traffic, and all of sudden I received message in webmaster tool that my site has been penalized in G. I thoroughly checked my site, there is no duplicate content, I never involved in buying links.

Any suggestions to overcome from this will be deeply appriciated.

 

Use only white hat seo method. Do not try black hat.

 

I never used any kind of black hat technique.

 

My website has this fault:" Show URLs: HTTP ‎(1)‎,Not found ‎(198)‎, Unreachable ‎(4)‎" I tried to remove and fixed it but it was not successful. Please show me how to remove it. Thanks in advance.

 

There is some problem with tour site content like title , keywords , images ... if you used duplicate content in your site , this can be reasons for penalized .....

 

Thank you. You can visit and help me? thaisonhotelgroup.com. My Website for SEO support.

 

Can you provide your site's URL?

Let us do the best guessing instead shooting the stars from here.

 

I think you have over optimized your site and that's what triggered it.