Learn about the archon wizard build in the embedded video above. For a wizard this is currently the fastest build to level paragon experience solo in patch 1.08. You could use either this build, a critical mass freeze wizard build, perhaps a black ice build or some other with a specific premade multiplayer game. Public games are just too random and unreliable. Often you will go into an MP5 or MP6 public game and at least one person in the game with you will have 40 - 70K dps which just isn't enough for them to pull their own weight. Another problem is that often people will disagree about what farming routes to take.
If you're into Diablo 3 and your D3 Wizard, I suggest you get to grinding out those paragon levels quick. Blizzard is talking about nerfing Barbarian's Wrath of the Berserker, as well as Wizard's Archon and Critical Mass Freeze builds. It may be a few months before that happens, but unless you play 10+ hours a day odds are fairly good that you'll want to get in your exp now before it is too late!