I didnt have anything usefull to do so Im doing this.
tip: 1
Keep your distance, if possible.
tip: 2
Tanks have about 1200 health, so pack a rocket launcher or two.
tip: 3
Use vehicles as a weapon.
tip: 4
Dont feed the witches.
Newb: Here, Witch!

tip: 5
witches are as fast as the motorbike, so this is where jets are most usefull.
Tip: 6
Use third person to look around corners to see if there are any zombies.
tip: 7
Expect the worse.
...More to come!