Progressive overload is the most fundamental principle through which muscle grows, and it's rather simple. Try to get stronger. That's what Milo of Croton did!⁣

Milo was an ancient greek wrestler, who use to carry a calf until it grew into a bull, building strength and muscle through the process. This is exactly the same concept you should apply to your training in order to make progress.⁣
In order for a muscle to grow, strength to be gained, performance to increase, or for any similar improvement to occur. The human body must be forced to adapt to a tension that is above and beyond what it has previously experienced.⁣⁣⁣
This principle involves continually increasing the demands on the musculoskeletal system to continually make gains in muscle size, strength, and endurance. Simply put, in order to get bigger and stronger, you must continually make your muscles work harder than they're used to.⁣ ⁣

However, while "simple" to conceptualize, it's certainly not easy. To be able to make progress, many other dynamic variables need to be held in place. Adding more pounds to the bar, adding one more repetition to a heavy set, making technique more efficient, recovering faster between sets, are all parts of progressive overload, and they can occur only when there's good programming behind. ⁣

Some things also come from experience though, so don't get paralyzed by over analyzing, and get to training! ⁣