Getting your site penalized by Google is very easy. Simply follow black hat SEO techniques to ensure your website is penalized by Google. Here are some ideas to implement:
Stuff your content with keywords. Using the same keywords too often on a page will help you get your site penalized quickly.
Link buying and selling
Start selling links openly on your website. Also buy links from ill reputed link-selling sites.
Spam the internet with links pointing to your site. Post links on blogs, forums and wherever else possible, using spam content.
Make two versions of your site, one for Google and the other for your users, both should be totally different.
Put invisible content on your page, by using color schemes similar to the background or perhaps exactly the same. You can also reduce the font size to a minimum or just simply use CSS to hide the content altogether.
Copy and paste content from other sites, Do not canonically link to the actual content page.
Past penalties for domain names and owner
While starting a website from scratch try using a domain name that has been previously penalized or if any of your other domain names have been penalized before, you have a very good chance of getting this new website penalized as well.
If you have more ideas for getting a site penalized by Google please post them in comments.