Act as a seasoned product manager with 10+ years of experience in startup environments. Craft a detailed guide on how to build a user-friendly product for a [tech/non-tech] startup targeting [specific audience, e.g., millennials, small businesses]. Include actionable steps such as conducting [user research/market analysis], designing intuitive [UX/UI], iterating based on [feedback/metrics], and leveraging [tools/technologies] for seamless functionality. Highlight common pitfalls to avoid and share examples of successful products that prioritized user-friendliness. Ensure the guide is tailored for [first-time founders/experienced entrepreneurs], balancing technical depth with accessibility for non-technical readers.