Much of hitting your drives longer has nothing to do with your swing itself, but how your swing interacts with your equipment.
Unless you’ve just gotten lucky, that your off the rack driver fits your swing perfectly, chances are you are losing 15 yards or more due to sub optimal trajectory.
And you’ll see that it eventually all boils down to a yards to cost ratio.
The perfect flight for your drives is greatly influenced by your clubhead speed. The higher your speed, the less launch angle you want. So for slower swingers, say from 60-80 mph, a high rainbow flight is best. These players hit the farthest at 16-20 degrees launch angle. For big hitters, a perfect drive looks more like a boring line drive, around 10-13 degrees.
Of course, wind and ground conditions will play a factor. So you must adjust accordingly for your home course.
We are looking to balance launch and spin to net a landing angle of about 35 degrees. This will optimize your driving distance under normal conditions.
If you play on harder conditions, like the desert, the best landing angle will be shallower, say 32 degrees. If your course is soft and/or wet, 38-40 degrees may be best for distance.
Most golfers with lower clubhead speeds, in my experience, could use more loft and a higher launch. High swing speed players (105+ mph) often have too much loft and spin. Their drives balloon and drop down very softly, costing them 20-30 yards or more.
At either end of the spectrum, say below 75 mph or above 105, most golf stores will not be able to fit you very well with what they have in stock. You will benefit greatly from a custom fitting on a launch monitor.
In the above example, the player is driving with a reasonably good trajectory. He is only missing around 7 yards of distance by landing at 41 degrees, which is a little too steep. His launch angle is a bit too high for 100 mph clubhead speed.
If he had an adjustable driver, this would be an easy fix simply by tuning down the loft perhaps 1 degree. He would buy a Trackman session and determine what adjustments he needed to make. If he had a fixed loft driver, he would have to weigh whether picking up 7 yards is worth the money to buy another driver.
You will always face a yards/cost factor. Is 15 extra yards worth $400? Is 30? In the above player’s case he could also make a subtle swing change to optimize the trajectory, but then there’s paying the instructor.