To get to RoT, I made spells that people could use, such as Greater Heal (don't make recall on Siege unless you just want to throw them away!!)
I copied books to around 30-ish skill from what I recall, then I switched to scrolls. I think I started with greater heal, after that I think I made invis, and blade spirits scrolls for my crafter to use, then gate, res, and summon earth elemental. It is fun to fill a few mage & necro books during training, which you can give away or sell, but that gets boring fast, and it is a pain storing all the scrolls and dumping them in the books. Other than to fill books, I didn't make multiples of any scroll that I didn't think there was a market for or that my own crafter couldn't use.
I equipped a nice inscription success chance bonus talisman and made spell books and other things in RoT, as soon as I was able. Oh yes, and a mana regen suit helps a lot.
-Skylark