Protect your totem: It is possible, with careful casting, to place a Magic Eye on top of a totem. This then protects your totem temporarily from Meteor Shower, Lightning, and Storm. Casting Iron Skin on your Eye will prolong itslife on the totem when enemies are nearby.
Quickly clear a POP: Run your wizard up to a POP, then cast Earthbind on yourself, then cast Tornado next to you, and watch your enemies disappear. When the Tornado has passed, cast a creature on the POP.
Wraiths on roofs: Stick a Wraith on a roof near a POP, and you will be able to see how many enemies are occupying it at any on time without your Wraith being spotted.
Lure your own: If you know there are a few Wraiths nearby, and your enemy is keeping them out of the way, cast Lure on your own creature and they will have to come into hand-to-hand combat to fight it.
Using a Totem of Pestilence - yours or an enemy's: infect a wraith, then use this to invisibly infect your opponent's creatures. Using Haste or Ornithopter can greatly increase your Wraith's range.
Use a Crocodile: Crocodiles with 'Excalibur', 'Iron Skin', and 'Bloodlust' are the most deadly things in the game for their price in mana. They are perfect bodyguards, and with 'Cure', they are immortal.