Act as a seasoned digital marketing strategist with 5+ years of experience in Facebook ad retargeting. Provide a detailed, step-by-step guide on best practices for optimizing retargeting ads on Facebook, tailored for [BUSINESS TYPE] with a [BUDGET RANGE] and targeting [AUDIENCE SEGMENT]. Include key strategies such as audience segmentation, ad creative optimization, and budget allocation. Highlight common pitfalls to avoid, such as [COMMON MISTAKE], and how to leverage Facebook's Pixel and Custom Audiences effectively. Ensure the response is actionable, data-driven, and includes measurable KPIs like [METRIC 1] and [METRIC 2] to track success.