How Do You Gain Weight?

I seem to be alone trying to put on weight. I sit all day, snack on chocolate bars, nuts, raw veg, potato chips. Most things I eat for main meals are meat and three veg, deep fried, stir fried, or with pasta-rice. I leave the fat on meat and skin on chicken. Drink a coke and few beers most days. Shudder to think of my arteries. How do you put on weight?