cover 2 and 3 drill progression

In teaching both of these coverages, I like to use half line drills. I almost never use the entire formation in drills. It's too many people to watch to make sure they are getting it right and uses up too much space. Set up two receivers and give them route combinations that are designed to go against those coverages while 2 of the DB are out set up in the coverages. That's my favorite way of drilling the coverages after they have been installed. As for teaching them.

Cover 2
Corner: Outside or head up alignment. DON'T BACK OUT. Pop the feet and be ready to move at the snap. Funnel #1 inside. If #1 leaves your zone inside, shuffle diagonally back to about 12 yards deep in the flat and look for #2 to be coming outside or for possible drag from the other side. DO NOT GET BEAT OUTSIDE BY #1 on a verticle. If it does happen, turn and run with him but get your head around to see #2. If #2 is staying flat, pass off #1 and get back to flats. If #2 goes verticle too, run with #1. I call that the sink rule. If #1 and #2 go vertical, you ahve to sink with #1 to give help to the safety. I know I'll get questions about defending the slant with my outside leverage rule, I'm hoping they run a slant b/c my OLB should be dropping into that area and will either get and INT or blow the WR up. Either way, I'm a happy guy.
Safety: High school, allign slightly inside the hash. Inside foot forward. Can be in more of a straight up stance than the corner b/c you need to have a better view of everything. At snap of the ball, back out and get wider. It took me until midway through my sophomore year in college to get this concept. DON'T GET TIED TO THE HASH. A cover 2 safety wants to get to the point where he is approximately splitting the distance between the sideline and the middle of the feild. From there he can get to the sideline or to the seam coming down the middle. He is reading #2 to #1. If he has 2 verticals, try to stay between both and don't cheat to either until the Qb has released his off hand from the ball to throw. Hopefully the corner will read things correctly and sink with the #1 going vertical.

Cover 3
Corner: Allign 8-10 yards deep. Outside leverage or head up on #1. 3-4 "read" backpedal steps at 1/2-3/4 speed. If #1 keeps threatening vertically, run with him, staying in backpedal for as long as possible. Reading the backfield. If Qb sets at 3 steps, he is driving on #1. If qb keeps going back to 5 or more steps, keep backing out. If #1 goes inside, alert SS or LBs for a crosser and look for #2 coming outside. Keep getting depth if #1 or #2 don't immeadiately threaten. A deep crosser will probably be coming from the other side of the formation.
SS: Allign 5-7 yards deep and 1-2 yards outside of #2 receiver to passing strength, unless he is a true twins and well outside. Then allign head up or inside. Must get hands on #2. Impede his progress down field. If he goes to the flats, go with him. If he goes vertical, jam him good then shuffle out to about 10-12 yards deep, looking to #1 to curl or come in. Same action if #2 goes inside. Be sure to let LBs know a crosser is coming. Again, read by looking into the backfield and reading the QB steps. Look for slants or hooks on 3 step.
FS: Allign 10-12 yards deep. Cheat to about the gaurd on passing strength. Same type of slow read steps as the corner. Stay over the top of everything. Read pass or run by reading through the middle three linemen helmet height to the QB. High hat-pass. Low hat-run. Also watch for quick set or long dropback by QB. Read all receivers on both sides. Stay deeper than the deepest guy. BE VOCAL!! you can see everything. Let everyone know everything you see. Crossers, curls, etc. Head must be on a swivel and this guy must be intelligent.

I hope all this helps. If you have any questions, let me know.