Are you looking for drills because you don't want to buy a 12* driver? Just like you saw a fitter for the club, you should take a lesson with a teaching pro. No one is going to be able to give you drills without knowing your swing plane, delivery, etc. Doing a drill that someone uses for their swing won't necessarily work for you unless your swing mechanics are identical.

It sounds like you were fit for the best driver for your swing. Go see a pro to fit you for the best drills if you want to change it.

Here is one suggestion I copied off the internet.

Setting up for shots off a high tee:

As in the picture below the feet are fairly far apart and there should actually be a little more weight on the back foot than the front foot

The ball is positioned inside the left heel and teed high

The spine should be tilting away from the target a little as you prepare to "swing uphill" 

Worth a try at the range. Practice, practice, practice.

What helped me was (1) teeing the ball up 1-2 inches higher than normal and practicing getting that feel for swinging up to make contact. (2) dropping my back shoulder and closing my lead shoulder at set-up (think of your trail side looking like a backward k) and holding that position throughout backswing to impact. There's also some decent YouTube video's out there, but be careful not to get lost in the clutter. Then there's always the lessons option

Tim- I also got fit into the 12 degree for 917 vs the 10.5 in 915. I have really worked hard on compressing the irons a bit more and taking a more consistent divot. For me this carried over into the driver. Right now the pro I work with has me standing a little further from the ball while hitting the driver indoors over the winter. We are trying to round out the swing to a more flat swing into the ball. He is trying to get me to feel more of a sweep it off the tee sensation. We have also moved my ball position forward as that had also crept back slightly for me. Hope these things might help you as well. Good luck I know you will enjoy the driver!

I practice in my garage with a tee stuck in a mat. I try to make my low point of my swing before the tee and try to clip the tee on the way up without killing it. Make sure you have a good set up and tilt away from target. Lots of info and drills on you tube can explain this better than me. Good luck

Hey Tim. I also have that problem. I'm working on decreasing the backspin and hitting upward. What I've been doing is moving the ball to about 1-2 inches inside my forward heel (left foot if right handed) teeing it lower, then at set up instead of putting the club face directly behind the ball I put it 4 inches or so behind the ball. In my mind this makes the low point of my swing a little further back and the result is an upward strike with lower rpm. It could be a mind trick I'm playing on myself. But after doing it for about 3 weeks I've seen a significant difference in backspin and distance. If you try it let me know how it works for you.