Get close, then get closer yet. 200 is much better than 400, and closer yet is better if you can.
Come to the Training arena and turn on the lead computing gunsight.
(control tab to enable friendly lock, then tab selects target)
Fly around behind them, watch how much lead you need, train that eyeball and brain. Then turn it off and practice, practice, practice.
Last if you see Tan ask how he does it, saw him land 8 in the zeke this week.
See if he'll let you tag along to watch, or join him in the cockpit.
Personally I also turn off tracers and use a small dot sight. I want nothing between my eyeball and the target to distract or confuse me.