Start with two anchors: your incorporation date and your FYE, then list the recurring workstreams—monthly close/bookkeeping, post-FYE accounts preparation, ECI (if required), AR filing, and the corporate tax return. Add a 4–6 week internal buffer before statutory due dates so approvals and corrections aren’t rushed. Finally, schedule three short founder reviews per year (Q1, mid-year, post-FYE) to check tax buffers, growth/audit risk, and readiness for filings.