There is no update for classifieds sites… But why you want black hat techniques?
Don't try black hat ethics once finalized then hard to get rank...
What are you doing SEO activities for getting rank?
Which update are you asking here? (Google Fred Update: Big Google Algorithm Update Links Related)
This is not officially announced still... May be affected but Google has not announced this update officially..!
You know why this update affects? Read this
https://www.seroundtable.com/google-fred-update-ad-heavy-low-value-23538.html
If your site has high ads, low-quality content and backlinks means, then it will affect check your webmaster tools if there is any message come, then you will do further..!
You can do it White hat techniques! Maintain own blog, guest posting, PR, etc
Use Google trends for latest updates, SEO related topics or keywords...
• You can target region wise classified (Like Local SEO)
• Build more PBN, web 2.0, blog comment & profile links
• Tiered Link-Building: To the main site, tier 1 & tier 2 sites
• You can reach on Social Signals
• Buying Links: 80% determinant of your Google ranking (Like Guest Outreach & Authority Outreach.!)