Online advertising expands reach and drives sales. Use Google Ads for search targeting and social media platforms like Facebook, Instagram, LinkedIn, and TikTok for specific demographics. Engage users with display and video ads on Google Display Network and YouTube. Re-engage potential customers through email marketing and retargeting. Amplify reach with influencer and affiliate marketing. Combine these with content marketing and SEO for better visibility. Success requires clear goals, audience understanding, compelling content, and continuous optimization.