I wish it were a simple matter of explaining in a concise step-by-step process - but it's not that simple. But there's something about making the perfect pass that just 'FEELS RIGHT' and the more experienced we become the easier it becomes...
Right now, I've played so much Madden that the 'right' pass is instinctive as having the hair on the back of you neck stand up when there's an unseen danger. Fortunately feeling so connected to the passing interface makes my hair stand on my neck figuratively as soon as I press the button to throw now when I've made a mistake (far too often I'm afraid). That's why I implore people to practice building their mechanics from the ground up instead of jumping right into the game.
Here's what I did/do, maybe it can help you feel like you're at one with the passing interface:
1) Set your clock.
Go into practice mode with the offense only and choose any pass play. Snap the ball and take a pass drop being sure to count each of your QB's steps out loud.
Don't throw... Just drop. Repeat it several times taking a 3-step drop, then 5, then 7. It's important that you count your steps aloud each time to set your mental clock.
2) Make the throws.
Now that your clock is set, choose a play with one or both of the outside receivers running a hook routes. Take a 5 step drop and throw the ball immediately after planting your back foot. Be sure to release the stick to allow it to return to the neutral position and hit the receiver icon button. The QB should take a 6th step in the direction of the receiver and fire the ball directly at his chest as soon as the receiver gets turned.
Keep in mind - if the ball goes ahead of the receiver so he runs a streak the pass came out too early. If he's stationary when the ball arrives, the pass came out too late. Ultimately the goal of this drill is to hit the receiver in the chest ON TIME.
3) Locate the pass
For this drill, imagine a defender somewhere in relation to the receiver running the hook and throw away from him. Take your 5-step drop, release the stick as in the previous drill BUT this time reengage the stick in the direction opposite your imaginary defender simultaneously as you activate the receivers icon button. Use this drill to get the hang of throwing high, low, inside, and outside of the receiver.
4) Add the defense
Now, exit Offense only mode and return to Normal practice with a defense. Choose the same offensive play from step 2 and 3 on offense and choose any defense that places your intended receiver in single man-to-man coverage. Take the same 5-step drop, let the stick go neutral, then reactivate it so you throw away from the real defender simultaneously as you activate the receivers icon button. If you have timed it perfectly, the DB should turn to run upfield just as the receiver turns to catch the ball. You should catch the ball with time to make one quick move before the DB can turn back around and recover. To late and the ball is caught with nowhere to run, batted, or picked. Throw too early and the pass is sight adjusted upfield where the DB can make a play.
5) Add more routes
For each route you want to throw, start without the defense and take the drop that syncs up with where the route breaks. For routes that keep moving, you'll need to work on getting the proper pressure to lead your receiver to more/less while slightly adjusting the trajectory of the pass.
As the throws become more instinctive, start throwing to receivers that are closer toward the middle to get the subtle timing and trajectory differences between a WR running a route and a TE running the same route. Soon, you'll have a basis for making all the throws you need for every route you want to use in a game.
Most important you won't need to look at receivers anymore. Come game time, you can focus your full attention on reading the defense instead and making the right throw to beat them - often without having to think about it.
Hope this helps,
Later