from my experience of being a wizard, and to save more questions if people read this. im gona post some tips, and answers, and techniques that will come in handy for playing wizard.
Team Playing:
Wizards need a team to play to their full potential, yes, you can hit thousands of damage, but a crit/double crit will kill you, particularly from a party mob.
in your party, make sure there is atleast one warrior and cleric, and a bard if possible, these guys will save your ass countless times.
Strategy:
wizards arent a hero, they dont run in close range and blow the crap out of everything in sight, yes, i know your lvl 20 nukes can do that, but you may kill 3 mobs in one go, possibly 5, but you cant take the chance of your nukes hitting low, which they can do, then youll have 5 mobs, probably one party mob attacking you, so youll die.
what you need to do:
stand back, alongside the cleric and bard, your very similar, your all magic based, so you have low hp, and your attacks are ranged, so no need to get close up and owned.
Make sure your warriors are up close, and knocking back the enemy, so it can get near you, also, if you have rogues, there knockback will do the same, and it is very helpful.
whilst the enemy is being knockbacked, your cleric should be making sure you have full hp, and you should have been buffed by now.
if your team is focusing on one mob, e.g a party mob, dont go using huge splash nukes, like the lvl 20 ones which can hit 5 mobs at a time, you dont want to ruin your teams effort by being overrun by attackers.
and ideal thing is to root the opponent, and make sure there under fear with the 2nd book electric nuke. then the warriors can attack them without getting hit back as much. then fire the small earth nukes, and fire nukes at them, as these will deal the most damage.
if your team is attacking several mobs, feel free to blast away your big splash nukes (lvl 20), but, try to stick to earth and fire (flamethrower) as these deal the highest damage.
other nuke uses:
there are several other nukes, which are also good.
cold/ice:
this is a large splash nuke, which can hit 5 mobs, this does medium damage, but it can freeze and give the enemies frostbite, thus slowing them down, and helping the other players alot.
lightning (lvl 20):
to be honest, this sucks bawls for damage, at lvl 22 i was hitting like 1.5k max with it. when i could hit about 2.5k with a lower lvl nuke.
but..... this nuke is one of my favourite (it looks cool aswell). this does rubbish damage, but it knocks back your opponents, several times, any enemies in the surrounding area will be knocked back far, and your team has a chance to heal, or to do more damage.
Solo Combat (mobs):
i have to admit, i like teamplay, but i grind my wizard in china, on my own, cos im a noob who seems to be on a team of people who cant play every time.
anyways....
soloing mobs, is simple, basicly, you cast your damaging nukes, the aim is to kill the mob before it gets to you, which is easy as wizard.
for higher lvl mobs, root them, then use fire and earth, and if they get close, electric knockback, and repeat.
for mobs about your lvl:
earth nuke (lvl 20):
cast this, and youll get aruond 5 mobs hurtling towards you, now, the second you cast this, target another mob, as it will 1 shot the first mob, anyway, as you cast it, select another mob, and select the first book earth nuke, so youll cast that straight after, then you will kill 5 mobs in 2 hits.
fire nuke (first book and 2nd):
simple enough, the fire nuke should 1 hit the, if not, cast a regular attack on them, and theyll be dead.
flamethrower..... this will kill a mob in 1 shot, but will do lame damage to surrounding mobs, and theyll probably kill you, as the splash from this is low damage, so try to avoid it.
electric nuke:
dont be an idiot, this wont kill them, but, if your gonna use this, use it with another nuke, like ice nuke, then it should hurt them.
lvl 20 electric nuke:
pointless for damage, it will get you killed, do not use this as a primary attack, only as a finisher or a last resort.
ice nukes:
these do medium damage, the first book one wont 1 hit a mob, but using it with another nuke (fire) or a regular attack will kill them, but this is a weaker nuke, thus not that good.
lvl 20 ice nuke:
huge splash nuke (5 mobs a time), also, this does okay damage, i can kill 3/5 mobs my lvl with this, so use this, then first book earth nuke, and youll be fine

, also it is handy to freeze them to run away (which wizards will do lots).
PVP:
against chinese:
suprisingly, euro arent that bad in pvp, aslong as the chinese char is your lvl, and chance is with you youll be fine.
theyll most likely imbue, and 1 hit you.
sooo....
root them first, then cast fear, this will give you 5 seconds or so, which will let you cast a couple nukes, hitting high (several k).
but, if you succesfully root them, fire your most damaging nuke whilst you have the space, so use earth or fire (lvl 20) and you should almost kill them, then you can finish them off with a book 1 nuke.
stuff against chinese:
do not!, i repeat DO NOT, use the slow lvl 20 nukes if the enemy isnt under root or fear, these are slow to cast, and the enemy will be on you and killed you before you can cast it, and even if you do manage to, you will be left with hardly any hp, and theyll be ready to attack more, and you wont be.
also, against chinese nukers.... you dont stand a chance, dont bother unless you can withstand their nukes, which will most likely kill you.
bow men are the same, theyll kill you quick.
the only way to hurt these, is to try and cast fear on them, and freeze them, as root wont do anything, as they have ranged attacks.
pvp against euro chars:
* uncomplete, i only know what to do with a couple builds, the others i havent pvp'ed yet
against other wizards:
100% roulette, you have the same attacks, same clothes, and probably same stats. this is based on who hits first, and you have to pray your nuke wont hit low. and i repeat, your identical, so even matched, and youll almost definetly 1 hit each other.
bards and clerics:
same as chinese technique, root, fear, freeze, nuke to death.
warriors:
pain in the ass, 100%, more annoying than chinese.
these **** will run up to you, knockdown you, and if that dosent kill you, theyll stab you, and that will kill you.
basicly, same as others, you need to immobilize them, BUT!, avoid slow lvl 20 nukes until youve immobilized them. fire a ice nuke book 1, root them , cast fear. then, do a high damage nuke like earth (lvl 20), then fire (flamethrower). then if that dosent work, repeat, or use electric lvl 20, and knock them back, and use a book 1 fire nuke. basicly, you need to keep away from them, and dont worry, its not being a noob, its what your build has to do.