You need to be in the gym five to six days a week and lift big, heavy, mostly compound movements. One muscle group a day, focusing in strict firm with consistent increases in weight
Then you need to eat for that - a diet rich in healthy carbs and animal protein and both non saturated AND saturated fats. Heavy lifting demands things if your joints and connective tissue that an uber liw carb low fat diet can't supply.
A modified seafood diet See food? Eat it.
Then sleep to recover
Bearish bullish builds are higher bf than the classic 8% jock body. Your solidity comes with consistent training and muscle maturity. Balanced fat intake is critical to avoid a softer mass, but you can't fear saturated fats either. They get a bad rap anyway, in my book.
But honestly - you're simply not lifting like an animal.
For good technique and smart training look for the writings of mass monsters like Rippetoe and Simmons and Holdsworth.