Up And Down Vs. Around
A driver and a wedge are built completely differently to accomplish different jobs. A driver is longer and flatter, and designed to launch the ball off a tee. A wedge is shorter and more upright, and shot height comes from the loft on the face. By adapting your setup to the club you're using, you've won half the battle. Using a wedge, picture your swing matching the upright shape of a Ferris wheel (left). With a driver, your swing shape will be more around you, like a merry-go-round (right).
It's easy for a player trying to break 100 to get overwhelmed by a lot of technical instruction. A lesson where you're bombarded by mechanical thoughts is a failure, because you can't incorporate so many things into your game at once. We always start our lessons with simple images, like the Ferris wheel and merry-go-round below. Getting a picture in your mind of swinging up and down or more around your body is a much easier and more productive starting point for understanding a swing than specific technical advice about things such as plane and path.
On shorter shots, it's tempting to freeze your body and try to make a smaller, arms-only swing. Even though you're hitting a shot 40 or 50 yards, you still should get your whole body involved in the swing. A simple way to visualize a good lower-body motion is to imagine a party hat connected by elastic to your right knee (right). The tip of that hat should point at your target when you finish your pitch swing.