Spells:
Magic Users begin with four spells in their spell books: Read Magic, Detect Magic, Scribe and one other 1st level spell (player's choice)
Illusionists begin with four: Read Magic, Detect Illusion, Scribe and one other 1st level spell (player's choice)
Clerics and Druids pray for but do not choose their spells at the beginning of the day. They can cast any spell available to them, unless they upset their patron deity (or neutrality, in a Druid's case).
Disfavor:
If the Cleric or Druid is about to upset their patron (or neutrality), the DM will warn them. Most disfavor is due to either praying or giving homage to a contrary deity, straying from their alignment, or failing to carry out their deity's will. A Cleric or Druid who is under disfavor has reduced spell effects (or spell failure, potentially).
Paladins can also cause disfavor by their actions. This can result in the loss of special paladin abilities for the duration of the disfavor.
Favor can be regained by sacrifice or special assignment by deity to regain favor. Details will be determined on a case by case basis.
Greyhawk Dieties:
https://en.wikipedia.org/wiki/Greyhawk_deities#Greyhawk_deities_and_the_folio_editionExample: Bob the Cleric is Neutral Good and worships St Cuthbert. He gives money at the Shrine of Ehlonna (also Neutral Good). This arouses the displeasure of St Cuthbert. Bob gets the notion of this in his conscience (the DM PMs his PC) that this ticks off his patron a bit and ignores it. Until he gives alms at a St Cuthbert Shrine all cure spells at made at -2 hp.
Example: Bob the Cleric is Neutral Good and worships St Cuthbert. He gives money at the Shrine of Erythnul (Chaotic Evil). This arouses the displeasure of St Cuthbert. Bob gets the notion of this in his conscience (the DM PMs his PC) that this ticks off his patron a bit and ignores it. Until he slays the head cleric of the Shrine of Erythul, he cannot turn undead or cast cure spells.
Example: Kate the Druid is Neutral, as all druids are. She helps a paladin (LG) to convince the others in the party to heed the ways of Law. She senses that this is upsetting the balance of nature (the DM PMs the PC) and ignores it. She loses the ability to talk to plants and animals until she helps a Chaotic player to heed the ways of Chaos.
The DM will always PM the player that they are at risk of gaining disfavor allowing the player to change the PCs actions.Alignment:
Very similar to above: if a character acts out of his or her alignment, they will be warned by the DM. If the alignment is necessary to the class (Rangers, Druids, Paladins, etc) then the character is likely to lose their special abilities of the class. Characters who act outside of their alignment will be at -1 for all actions for a day (24 hours). If they continue to act outside of their alignment, they will incur more negatives to rolls. Even worse negatives can occur if the PC acts far outside his alignment (at DM's discretion).
Example: Marcus is Chaotic Good. He regularly is mean to undeserving NPCs and steals a piece of bread from the local baker. He is not being Chaotic good, but more neutral or evil. His conscience begins bugging him (the DM PMs the PC) and for the next game day (24 hours) he attacks at -1, has +1 to his AC, and has -1 on all saving throws. He then leads the slaughter of orc children. His conscience begins really bugging him (the DM PMs the PC) and for the next game day (24 hours) he attacks at -2, has +2 to his AC, and has -2 on all saving throws. If he acts within his alignment for the next 24 hours and he begins feeling normal again.
Switching alignment:
If a character choses to switch alignment (usually due to acting that way for a while), he may do so with a loss of level (and associated hp, etc) if the alignment is adjacent to the current one (e.g. from Lawful Good to Lawful Neutral, Neutral Good or true Neutral), two levels if two steps away (LG to LE or CG), three levels if three steps away (LG to NE or CN), and four levels if they choose the opposite alignment (LG to CE).