For a long time, when I played as a zombie, I used a method in which I predicted a player's movement using only the W key.
I think this has advantages and disadvantages and in the hands of a skilled player, it could be quite overpowered.
Q: So how does this work? A: When a player is holding a flank using either W and A or W and D, instead of trying to predict by going to other way alltogether, one could just only press W, and you would close the distance anyhow and lose less distance if you predict wrong. This works because in a flank you are generally always behind a player when they run. Here's a visualization.
W key only prediction, when done correctly should, on your screen result in you being or almost being inside the player character. This way you have made a very bad situation for the human.
Pros: A small mistake for the human could result in a successfull kill. Having said that, someone who has higher ping is especially weak against this method.
Less distance is lost than a traditional prediction.
This move exploits minor bugs with the hitbox, which will result in some infections looking as if you reached the human on their screen
You're a very annoying zombie to deal with.
Cons: Your vision gets limited a lot so you will have to practice a lot in order to do this efficiently.
It is very easy to escape from if the human has lower ping.
you have to hold the flank very close in order for this to work.