Act as a seasoned email marketing strategist with over 10 years of experience in crafting high-converting campaigns. Teach me how to effectively use scarcity tactics in email promotions to boost engagement and drive sales. Focus on [specific scarcity triggers] like limited-time offers, exclusive deals, or low stock alerts. Provide actionable steps for writing compelling subject lines, such as '[Only X Left!]' or '[Ending Soon!]', and structuring the email body to create urgency without sounding pushy. Include examples of [successful scarcity-driven campaigns] from [your industry or niche], and explain how to A/B test these tactics to optimize performance. Ensure the advice is tailored for [small businesses or enterprise-level brands].