How do you master a play?

Ive heard some people say that when it comes to picking plays in Madden it's quality over quantity and that a good madden player only needs 5-8 plays they can rely on. After switching back to the NFC pb I have many plays that I'm familiar with but I don't feel like I've mastered any of them. What do you do just run a play vs every coverage in the game and see How it plays? In practice mode I'll always run a play against Cover 3 sky and other C3 defenses,Cover 2,Cover 4,Cover 6 and MCV. Cover 6 is one of the easiest defenses to recognize and isnt hard to beat so I always try to have a C6 bomb. I know some players will run 1 or 2 plays over and over with adjustments and it can be difficult to stop. I do like having a big Arsenal though to be able to show my opponent something new from myself but its definitely best to master a few plays for every situation you might face. I always try to have a checkdown or another strong route I can look to in case the user is covering my first read which happens often.

I think you're correct that mastering a play involves knowing the how it runs against all the different coverage concepts and some adjustments you can make so that it beats more/different coverages.

Another key component to mastering a play in my opinion is the timing. This is mainly for passing plays but knowing when to throw the ball so that it gets to the receiver at the best possible time is a good skill.

Knowing how your field position impacts the play is crucial part to mastering a play. You need to know how being near the middle of the field or on the left or right hash can impact can impact the play to master it. If you in the redzone what's the best distance to run the play from.

The last component I think is important to mastering a play is having a scheme. You need to have an understanding of what beats your play. With this understanding you then work on adjustments or other plays that will compliment it well. Knowing how to setup plays so that other plays succeed and you keep your opponent guessing is a critical component to a good offense 

I'm nowhere near a madden pro so I could be off base here