Pokémon GO may be a simple to learn game, but there can actually be a little bit of trick to mastering the different elements of the game. One of those elements is the art of the Pokéball toss to ensure a better chance at catching certain Pokémon, and a user on Reddit details how to use something they're referring to as the "L" Throw to make catching Pokémon that much easier. The L Throw is said to increase the accuracy level of the toss, so if you've been having more trouble catching Pokémon at all while you play, this might be a method worth trying out.
All users have to do when they want to toss out an L Throw is just drag their finger on screen out from the middle towards the left edge (or perhaps the right as it should work in this direction too) and then upward to fling the Pokéball just like they normally would, not forgetting that they will need to release their finger from the screen once the Pokéball matches up with the height of the Pokémon. At this point, letting go of the Pokémball allows for an incredibly accurate toss, and the better accuracy your throws have, the better chance you have to actually capture a Pokémon without it escaping and running away.
Quite a few other users seem to confirm that they have had much better luck using this method of throwing out Pokéballs compared to simply flinging them upwards. Those worried about whether or not this is a cheat or an exploit can rest easy as it's stated that this is neither of the two, meaning it's safe to do when you're out playing the game. Homu, the Redditer who posted this toss method, states that while it does appear to work by dragging your finger to the right of the screen too, they have had less reliability when moving their finger this direction. Some players are also reporting that they have had increased accuracy for throwing Pokéballs when trying to put a curve on the toss. If you play Pokémon GO, give either of these throw methods a try and see if they help you catch more Pokémon.