Eat often
Eat MORE than just being full. Almost like a kid and ice cream.
EAT CARBS! And eat them with, or at least close to, your meat/fat.
Lift weights, lift heavy, get near to/achieve muscle failure often
Eat ALOT
Eat MORE than just being full.
Get plenty of and good sleep at night.
These are all very good points. Unfortunately, they only apply to a healthy person with healthy GI system. Those who have difficulty gaining weight usually have some kind of GI problem and above tips can easily aggravate the situation.
I also do not believe in so called "fast metabolism". In a healthy system all extra (unspent) sugars will convert into fat by the liver for use during leaner times. If this does not happen then GI system is not working efficiently and there is some kind of problem.
If I eat more carbs I get health issues that make it even worse. Also eating more than just being full only slows down digestion/absorption and puts more strain on already weakened GI system.
The solution is to recover your GI system. Surely, easier said then done as I am still trying to recover my digestion.
So far I have found that eating when hungry works the best. Eat something small and salty 10-15 min before the meal. Eat in smaller portions. This way stomach gets empty rather quickly and will be ready for the next meal. When I eat big portions it tend to sit in the stomach forever.
I avoid starchy food as they give heavy bloating. Fruits and leafy greens do not appear to give me bloating. A slice of bread also does not give bloating.
Rare meat and fat in moderate amounts with little salt digests pretty quickly.
I really hope I get to the point where eating more carbs will result in some fat deposits. So far it is not the case.