This document discusses various tactics for startup growth, including growth hacking, models, metrics, email marketing, acquisition, and retention. It provides examples of key metrics like CPA, retention rates, and lifetime value. Tactics covered include testing different subject lines and copy in emails, segmenting lists, optimizing funnels in Mixpanel, and focusing on retention over time through simple engagement processes. The document emphasizes testing ideas and optimizing for goals and metrics on a weekly basis.