To me it's really simple; it's the little things, lack of discipline and a lack of attention to detail.
You don't have to blow everyone out and you don't have to bomb it down field all the time when you can get the 3 to 5 yard passes and runs all day long and you don't need all-stars at every position (See Miami-which now has a better record and New England).
In these days of parity, coaching and player development matters more than ever.
Having a competent staff that can focus on and teach the following will give you a chance to win almost any game you play:
Game management:-control the clock, use your offense to rest your defense and keep your defense fresh so they can demoralize your opponent.
Protect the ball and don't turn the ball over - EVER!! (Even when it's late in the first half and it looks like it will work as a punt in the worse case scenario.)
Know your job!! COLD!! Know the rules, your assignments, the play book and ALL situations so they are merely unconscious reactions during the game.
Don't commit penalties - be disciplined enough to not commit penalties & be knowledgeable enough to know when your about to commit one, so you don't.
The short game works too!! You don't have to commit to an extreme vertical offense. Moving the ball forward and keeping your defense off the field for a few series might be exactly what they need to be fresh in the 4th quarter. Plus if you can get 3-5 yards every down, you will never be stopped. Use the high percentage short game to open up the low percentage vertical game, NOT THE OTHER WAY AROUND!
Play as a team at all times! Offense, if you can't score, then stay on the field as long as you can to control the clock, wear out the defense and keep your defense fresh. Receivers, if you can't catch the ball, don't give up!! Protect your QB and keep the defense from intercepting the ball at all costs---this is one time where you are allowed to commit a penalty if that’s what it takes.
If they could do all of the above on a consistent basis, we would have already clinched the playoffs and maybe the division.