Act as a seasoned newsletter strategist with 10+ years of experience in monetizing niche audiences. Provide a detailed, step-by-step guide on the best ways to monetize a [TYPE OF NEWSLETTER, e.g., tech, finance, lifestyle] with [TARGET AUDIENCE SIZE, e.g., 10K, 50K, 100K+ subscribers]. Include strategies such as sponsored content, affiliate marketing, premium subscriptions, and exclusive partnerships. Tailor the advice for [NEWSLETTER FREQUENCY, e.g., weekly, bi-weekly, monthly] and highlight the pros and cons of each method. Offer real-world examples and actionable tips to maximize revenue while maintaining audience trust and engagement.