If I was to start from 0, I’d tell myself this: 1. Your aerobic engine is everything. Learn effort, not pace! Don’t chase numbers on the watch. Spend more time making easy pace ridiculously easy and stack easy days. Forget HR if you’re a beginner and focus on effort instead (this might change from time to time because of sleep, weather conditions, altitude, time of the day, elevation, fueling, etc) 2. Know your training zones, if you can, get a lactate test. It helps you identify your true easy, threshold, and high-intensity zones so you’re training with purpose instead of guessing. Most marathon improvements happen from spending lots of time at the right intensity, not by running every session as hard as possible. 3. Don’t prove fitness in training, protect it! Stop racing workouts. Fitness compounds, and fatigue does too. Race day is where you prove fitness. Respect the workout, and have some pacing discipline. You always want to finish a quality session thinking “I had one mor...