Muscle 4 Hardgainers

I need to gain weight fast, help me please!”
“I really find it hard to put on muscle. What is the best way to achieve natural weight gain? I don’t want to take weight gain supplements.”
“I eat and eat and eat but still nothing! How can I gain weight? What’s the best weight gain supplement out there?”
I need to gain weight but I don’t know what to eat to gain weight. Can you give me a list of food to gain weight?”
These are some of the most frequently asked questions I encounter in relevant forums, so I thought I’d create a step-by-step guide that will address everything one needs to do in order to achieve healthy weight gain.