
It doesn't take that long to get to this level of magedom if some spells get spammed, though. Only if (let's say) somebody is totally new to the game, or if somebody is going for something unconventional, like a non-confrontational-type of mage, might they need to plan ahead.
Morrowind is nothing like the others. I don't know about Daggrefall yet, but MW is definitely more difficult to approach than Arena is, even with Arena's forced classes. And I've had to rethink a lot of ways I'd normally game, just to make my mage successful in this game.
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Tip 1: Restore Magicka potions seem like they're almost extinct in this game. Even as an alchemist at Journeyman level (three effects can be seen when making potions) I still haven't figured out what to mix with comberries to make dozens of these potions!

I did not know that all Mages Guilds have a respawning chest though, called Mages Guild Supply Chests. These include 10 free mana-restoring potions.

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Tip 2: The Spellmaker is a mage's best friend. This becomes more apparent especially as the game levels upward higher and higher. My opinion now: I never really found the Spellmaker that useful in Oblivion. In that game, it can be merely used to make some spell effects more creative, effective, and/or efficient. But in my opinion, I never actually needed to use the Spellmaker in Oblivion. It's more of a convenience than a necessity (in my opinion).
Well in Morrowind, you really are going to NEED to make your own spells, and you'll also need to know how to use the spellmaker. Thank goodness we don't have to get into any university just to create our own spells. Nor do we have to be a Mages Guild member. There are some temple-dwellers, and probably a few other NPCs out there, who can help us make spells. All we need is some gold, and also to know the effect we're trying to work with.
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Tip 3: Conjuration levels up slowly in this game. MUCH slower than in Oblivion. In OB, those who spam this school will be guaranteed to hit Journeyman level within a month, if they play frequently enough.
And this seems to be a reaction against Morrowind, in which Conjuration levels upward extremely slow, especially if it was started as a Minor skill rather than a Major.
And here comes my very first use of the Spellmaker. There's a reason Conjuration moves upward so slowly: it's because a lot of the default Bethesda-made spells (Summon Bound Dagger, for instance) last 60 seconds each.

Each time that dagger is cast, 3 points get added toward the Conjuration level-up of 100. Doing the math, this means that somebody diligent enough to keep casting this spell will spend thirty-three real-time minutes (I think I got my math right...) doing nothing but waiting to recast that silly spell over and over.
BUT, a trick I learned is to simply make a Bound Dagger spell which lasts 5 seconds, not 60. Voila. When this version is cast, have a look at the number of Conjuration points the game gives toward 100. It's still 3 points per summon!

Still though, if you are like me, and want to see your character become a conjuring fool in no time, this is a good way to go.
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Tip 4: Last one for today.

A lot of default Conjuration spells, lasting 60 seconds each from Bethesda, will have rather high magicka costs, not to mention some pretty dismal success ratings.

But a more advanced spell, such as Summon Lesser Bonewalker, cost my mage almost 40 points of mana, with a really [CENSORED]ty 61% percent spell success rating.

The way to fix this is to use the Spellmaker again. Make a Summon Bonewalker spell which lasts maybe half as long. Matter of fact, I made a spell for my mage which summons this undead for 25 seconds instead of 60. Voila. Magicka cost went way down to just 17, and the spell failure rate is just 3%.
Time for some pwnage!