As we know that Google is most popular search engine and it always try to updates its algorithm to improve search engine performance so now what are the things to be keep in focus to get good ranking now days.
•   Submit website with Unique content
•   Submit on related sites
•   Submit website on High PR and reputed sites.
•   Stop Black hat seo and over optimization

Keep working for building natural link .Don't make spamming by doing over with in website optimization or in Link generating process.By following Google rules one can stay with Google ranking.

After penguin update we should focuses on (a) building our site with unique good quality content, updation of our site with fresh content regularly. (b) Avoid keyword stuffing. (c) promote content on that sites which are relevant to site theme.

Things to focus on:
>Do not stuff the content with irrelevant keywords.
>Do not use any kind of hidden text or hidden links.
>Avoid tricky redirects.
>Avoid duplicate contents.

The well aware SEOs are already following these guidelines to avoid being hit by penguin update.