I believe that we are the most strategic class in the game.
I listed the strategies by orientation sub-divided by level ranges.

PART 1.
Mixed Group Strategies.
You have all heard, "Wait Until 50% damage." There is a little more to our
class than that.

Universal Levels
1) I see many wizards cast Root spells while the melee is going on. Do you
see anything wrong with this? He's not going anywhere, save your mana for
better things.
2) If you have a weapon, a little melee can go a long way. It definitely
won't be much, but that 40-50 points that you do before you begin your
casting, could be the difference. Especially, if you're fighting multiple
mobs. I'm sure you understand.
3) I experience serious lag when it comes to the mob's health bar. I
actually learn how much hps a mob has and have it written down, then I watch
the tanks damage and have a good idea what the other classes are doing as
far as damage goes as well. So as soon as 60% gets around I know it
immediately (I'll talk about the 60% soon). Whether your group admits it or
not, we are the generals of the group. We have to know what the other
classes are doing and what they are capable of and what that mob is capable
of. Don't be afraid to take notes on mobs. Ask your group members what they
do and if their spells have a side-effect damage and how much. I have all
kinds of crap about my computer when I play, I have a sheet for every zone I
have visited. (It doesn't feel right to give away all the mob info, and it's
not that hard to get anyway.)
4) 50-shmifty. That isn't entirely accurate. Keep a mental account of who
attacked the mob, and who has done the most damage, and how fast they damage
the mob. If the aggressor is the one who has done the most melee damage
you're safe to cast at 60%. If the aggressor is the one who has done the
most melee and can get 3 melee hits fairly readily, you're casting mark will
be greatly increased to about 70%. By the time that you're with warriors
that get 3 hits readily your casting times will be long enough for you to
cast around this mark. You will be attacked sometimes with this, so if there
is no hurry, it is cool to wait.
These strategies are very aggressive. To me, items and knowledge is what
makes up this game. EVERY item that is worth getting is camped. And we all
know that no one thinks about anyone but themselves when that rare mob
spawns. WE ARE THEY KEY TO GETTING THAT MOB. We must do the most damage
(duh). If we get attacked, we are not doing the most damage. I wrote these
previous strategies for these situations. If you're grouped just for exp.
and fun, it isn't as important to be this aggressive. But it is always great
practice.
*Note* These strategies have made me somewhat known. I always get asked to
group in HighHold and the like, even when I'm just passing through. If
you're having problems find groups, these strategies will help fix that.

Low Levels (1-15)
There really isn't a whole lot to cover here that I didn't already. Low
level guys are given more room to be impatient. If you're grouped and the
mob comes after you, you can root it and back off. Soon the mob will we more
worried with the guy putting a sword in his head than you.

High Levels (30+)
1) I use my stun spell right away if it's white or lower. Yellows I stun if
I am only going to fight a total of 3 mobs before I can meditate. Red's,
hehe, this can be fun. I cast one stun on the red if there will be no more
reds. They resist it often and if it's going to be a long battle, any mana
is precious.
Your warriors will love that spell though they probably won't tell you. It
isn't a flashy spell that we're used to but if that mob can hit for 40dmg, 6
seconds of no hits is heavenly to your tanks and the people who have to heal
them.
I only cast it once, resisted or not, just once.
2) Aren't resistances fun? Talk about a pain in the ass. I have found
something to do when we are totally resisted. Cast cancel magic on the mob.
Very many high level mobs can cast spells, even though you might not know
it. Cast it once, suddenly the mob stops to recast its buffs. That is what I
like to call an impromptu stun. I found some mobs that I thought had no
magical abilities actually do, once their buffs are gone. For some stupid
reason, they will stop melee to cast.
Hey, I do what I can... when I can't.

PART 2. Wizard-only groups.
The best tag-team you ever seen.

I don't know how many of you have tried this, so I will talk as though this
is a new idea. I am not insulting your intelligence.
This grouping style gets some serious results but only in open areas. If you
can find a room that matches my dimensions, go for it.
These strategies are formations, not really spells. So there is no level
range for this.
It is very important that everyone uses the same spell. It is almost as
important that everyone be the same level. Just don't attempt this with
someone who is high enough to use a different set of spells.
To explain distances and areas, I will use the screen. So be in 1st person
perspective until you get the hang of it.
Most Important. I only recommend 1 mob at a time, unless you get really
advanced skill in the 5-6 wizard grouping.
I will use groupmembers A, B, C, etc. A is always the puller. For Advanced
grouping, the last member would be the second puller.

Duo-Wizards or the 'I' formation
This can be used on anything that is the lowest red and lower.
A goes and gets a mob while B follows him, keeping A in the middle of the
screen. A finds a mob turns on auto-attack and melees, while B casts a spell
(shock spell, bolts will be obstructed). Once the spell hits, A turns off
auto-attack and retreats by walking backwards, while B turns on auto-attack
and advances. The mob will then decide that B looks like a better choice for
a meal. Once A has B in the middle of the screen the process continues.
Repeat as desired.
If the mob likes someone, have the other person cast spells until the mob
comes after him. Then return to the normal process.

* The following is strategies that closely resemble a game of "Hot Potato" *
3 Wizards or the Power Triangle
A, B, and C run around together until they find a mob. Once someone finds
something B and C form a line and face each other keeping the other in the
upper 1/4 of their view screen. A casts and once the spell is completed,
runs to a point that puts B and C at opposite ends of the screen. Once the
mob joins up with A and the two are meleeing, B casts the spell. Once the
mob runs to B and they are meleeing, C casts. Get the picture? It's fun
watching the mob run in circles until its dead.

4, 5, and 6 wizards.
This is the same as the 3 strategy just use Box, Pentagon, and Hexagon
formations.

* Relates to 3+ groups * If a mob, for whatever reason, sticks to a caster
have the person who would be next in line root or enstill it (whatever your
group decides) then the following person cast damage at it and so on. If
you're only in a 3 group, skip the person who was stuck with the mob for a
rotation as well.

The most important thing in the Part 2 strategies is to stay calm. These
strategies look great on paper, they work trust me, but the real key is
knowing what to do when something goes wrong. The true strategy lies in
staying calm and figuring out very quickly how to remedy what went wrong...
something I am still working on.
Whatever action you decide to use to fix the problem make sure its the
caster that is after the guy getting hit that makes the action. Confusion is
the worst thing in these strategies.

I hope this helps you learn more about your class. If you have anything to
add or if there is something I could've stated better, please share it.
I am happy I could help.
If there is anyone on Karana that is fairly high, I am looking for a few
items, hehe.

Good luck guys,
Telor Strifesage on Karana