Getting Better at Madden

[nation]

Ok, so I don't know as much about football as I should. I pretty much randomly call passing or running plays, and there is no rhyme or reason for my defensive play calling, aside from nickel or dime in 3rd down passing situations, goal lines at the goal line, etc.

Anyone have tips for which plays to call when? Obviously there is tons of little stuff, so if everyone can add little tips this thread can help a lot for beginning Madden players.