Washing your hair should be nothing, I repeat NOTHING, like what you see on shampoo commercials. They show some girl lathering up every last inch of hair and swirling it atop her head in a big, bubbly mass.
Do you know what that’s doing? It’s drying out your already delicate ends and wasting your shampoo.
Shampoo is designed to remove oil, dirt, and other gunk from your scalp, so that is exactly where you should be focusing your efforts. Apply the shampoo close to your scalp and rub it around. If it's lathering up a little, you're good. No need to have a mountain of suds.
Not spreading around enough? Before reaching for more shampoo, try dipping your hair quickly in and out of the water stream and continue massaging it around. This should cause the concentrated product to spread more...unless it's a cheap shampoo. Then you're just watering it down even more than it already was from the factory (if that's even possible).
Remember, you don't need to concentrate on working it all through the ends.
Additionally, the size of your ponytail will let you know how much shampoo you need to use. If your ponytail is the size of a dime, you need a dime-sized amount of shampoo. The same with nickel or quarter sized ponytails.