Don't stop to pass, key bind it and pass on the move. It drives me crazy when I'm in the EZ and someone runs through the pit and stops for 3 seconds to try and find pass and in the meantime I get pulled, knocked down or exploded.
You should also ALWAYS be looking to pass. Even if you just got the ball and you at 100% health. If someone is further ahead or in a better spot you should throw them the ball. Make sure they aren't surrounded first. The ball is supposed to go to the person closest to the center of the ground marker but due to latency and internet black magic that might not always be 100% accurate according to what you see.
Watch for leapers waiting around for you to pass to an obvious person. Timed correctly their leap will intercept the ball. So if there is a teammate jumping up and down on the cat walks with a marauder standing 20m away just staring at him he is probably waiting for the pass to leap and intercept. This will be especially important in tentative 4.0 since everyone will be able to leap/blink.
Lead your passes. If someone is running across the fire pit don't aim for the fir pit like a jerk, throw it in front of them so they run into the AoE instead of out of it. You can also do this if they are close to an enemy. If the bad guy is on the left and your teammate is on the right throw to the right so that your teammate is just barely in the circle, this way they will more likely be closer to the center and it will be harder for the enemy to get in the AoE.