Here are a few more ideas - don't bother with many reciprocal link exchanges, don't create multiple sites with similar content, don't use what google considers to be doorway pages, and don't buy links from low quality blogs
Just keep working on SEO. Make sure your content is high quality, updated on a regular basis, and also offers value to the reader.
The only solution to all these problems lies in the quality Links. The better you have the more standing you have in Google.
if ur site is banned then ...... u can do nothing , close the site and start a new one. if ur site page rank has come down , try to built quality page-links , (backlinks) and not from some blogger site , or something like that. Keep all page-linkings to a minimum and stop all kinds of hideout link practices. *Note : panda and penguin algorithm update of google are two different things do not mix each other.