[Radek]

Note that you need spell effects rather than spells themselves. Once you know "fire damage" (some "fire damage" spell, for example, the Firebite spell, is in your spellbook), you can prepare any "fire damage" based spell at any spellmaker. Every Mages Guild contains a spellmaker. You need not be a member of the guild. Most of other guilds contain spellmakers, too. Moreover, there are "freelance" spellmakers in the game, for example, the Destruction master trainer near the Piernette's house.
As far as the spell effects are concerned, check the Mages Guilds, temples, Telvannis, or Imperial Cult. Every time you see that somebody is offering "spells", check what is he offering. Learn new spell effects (buy cheap spells with the desired effects even if you see that the spells themselves are useless), go to nearest spellmaker and prepare the spells you want. Now, you can delete the bought spells from your spellbook because the new spells contain the spell effect as well so that you will know the spell effect even after deleting the bought spell.
This way, you will create your spellbook in the game.