How to throw a Pokeball far in Pokemon Go?

In my experience I just swipe the full length of the screen really fast and it goes pretty far. Also a little trick is that after a Pokemon breaks out once it tends to move farther back so if you leave the battle and try to catch it again it resets back to being closer. Just be careful that if it takes too long and you back out the Pokemon might despawn and be gone.

• Increase the velocity and duration of your swipe gesture. In my experience these two factors have the largest influence on the distance the ball travels.
• Position the Pokemon at the bottom of the screen. Doing this will increase the release angle (with respect to the Pokemon) of the arc that you throw your ball thus increasing the overall distance the ball travels. Note, this only applies when AR is on.
• Practice, practice, practice.

Learn how to curveball. Due to the nature of the way we hold our phones, swiping in a long motion results in a natural curved motion. If you learn how to curveball, you can account for curve and learn how to get excellents on every throw.

The jist of getting pokemon really far away (and catching pokemon in general) is:

• Spin the ball before getting ready to throw it - that is, move it in a circular motion. You can spin it quickly and it will spin for 1-2 seconds after you stop spinning. The spin amount is irrelevant past a certain point..from what I've experienced you just need to make sure it's spinning faster than 2 rotations per second (this is a guess, I don't know the actual numbers).
• When you do move your finger to throw the ball, move it from corner to corner (opposite corners) in an arced motion. Your finger will stop and start at a corner, but it's not a straight line. It's a mild arc and your finger shouldn't stray more than an inch or two from the line between the corners (the peak of the arc will only be an inch or two away from the straight line between the corners).
• Do NOT focus on throwing extremely quickly. What happens is your finger isn't tracked as correctly and the ball is released early or at a lower velocity than if you just ensure you're making contact with the device for the full swipe. Swipe at a moderately fast pace, but do so in a controlled manner so that your finger stays in contact. If you curve the ball enough (Not a specific amount, just get it past the threshold so it's curving a second or two after you stop moving it in a circular motion) and move your finger from corner to corner, it's just a matter of when you release your finger from the contact of the screen to get farther distances. It depends on the size of the device, but for example, for me with an iPhone 6s, Mankeys are about 1/2 the screen, growlithes are 2/3 of the screen, and ponytas/rapidashes/dragonites/blastoise/venusaur/charizards are all 100% of the screen.

I don't even have to aim because the curve + distance means an excellent every single time as long as I keep my arc motion consistent and steady.

Best practice is to turn on AR put your pokemon at the bottom of the screen and use a normal throw