Act as a seasoned startup advisor with 10+ years of experience in equity structuring. Provide a detailed guide on how to fairly and strategically allocate equity among founders, employees, and investors in a [TYPE OF STARTUP, e.g., tech, healthcare]. Include considerations such as vesting schedules, dilution, and valuation. Address common pitfalls like [COMMON MISTAKE, e.g., over-diluting founder shares] and how to avoid them. Also, explain the role of [KEY DOCUMENT, e.g., shareholder agreements] in protecting stakeholders. Tailor your advice for a startup at the [STAGE, e.g., seed, Series A] stage.