Custom spell creation Question

[Melandril]

In general, how do you successfully get a spell idea from your head into a character's hands/inventory/spellbook?

With that as my general question, I tried the following and ended up with a spell marked as CLR (255)
1) found a `spells_new` entry to use as a template for something basic: water pet 2
2) inserted the template back into the `spells_new` table and set the idea as max(id)+1 (ended up being close to 30000, so I set it to 30000 instead)
3) changed classes2 to 2 and all other classes# to 255
4) changed the column that starts with Zone from the water pet 2 entry to BLpet85
5) looked in `npc_types` and saw BLpet70 as the highest npc_type with a name like '%blpet%' and changed my spell to use BLpet70
6) edited the spells_us.txt and added an entry for the spell at id 30000
7) found an `items` template for a scroll (Yaulp V if anyone cares), copied and inserted into the bottom, changed the scrolleffect to my new spell id (30000)
8- in game, the spell showed up as CLR(255)

Found one forum entry that suggested that the spell id might be the issue, so, finding no spell of id 1, I tried changing the spell to make it spell id of 1. The result was a spell scroll that did say CLR(2) but when I tried to scribe it, the spell book bugged and told me something to the effect that the spell id was outside of the proper range.

So, what do I need to do and know to create spells? What are the common gotcha's? (Less import but something useful to know, how do I alter the text description on the scroll? is that a field on the `items` table I simply overlooked or does it link on a field in that table to another table?)

Thank you