The only advice I can offer with bows is to expect to miss your first shot, and use that shot to calibrate your second. You will almost always have to lead your targets.
For targets coming toward you, but zigzagging, do not try to follow their zig zag, instead, gauge how wide a distance they are making with the zigzags, such as a span of lets say 6 feet for example. Once you gauge the span, fire your arrows at either the zig, or the zag, but not both.
Please excuse my terribad drawing skills:
As I try to illustrate, a zigzagger will typically still maintain a pattern to his approach, so it is up to you to choose either his zig or his zag to fire upon as the green arrows suggest.
I hope that makes sense :(