1. Eat more calories than you burn: The key to gaining weight is to take in more energy (calories) than you burn. This will put your body in a caloric surplus, allowing you to gain weight. 2. Eat plenty of protein: Protein is an essential macronutrient for muscle growth and maintenance. Aim to consume 1.4–2.0 grams of protein per kilogram of body weight per day. 3. Increase your calorie density: Consume more calories in less volume to make it easier to take in a larger amount of energy throughout the day. This can be done by adding in healthy fats such as nut butters, avocados, and oils to every meal. 4. Prioritize strength training: Strength training is essential for hardgainers as it helps to stimulate muscle growth. Focus on compound exercises such as squats, deadlifts, rows, and presses. 5. Don't forget to rest: Rest is essential for muscle recovery and growth. Aim to get 7–9 hours of sleep per night, and take at least one full rest day per week.