The "90/90/1 Rule" is a productivity tip that suggests dedicating the first 90 minutes of each day to working towards a big goal. The idea is that by focusing on your most important task first thing in the morning, you can make significant progress towards achieving it over time. The rule recommends committing to this practice for 90 days straight, with no distractions, interruptions, or excuses. By the end of the 90-day period, you should have developed a habit of prioritizing your most important work and making consistent progress towards your goals.