I use these guidelines for animals. Most creatures should have a special talent bonus, ranging from +10 to +50 for certain skills, such as stalk, perception (perhaps a specific sense), hide, ambush, climbing, etc.
Then I determine how important the skill is to the creature and how much time and effort they would spend mastering it versus relying on pure natural ability.
Survival depends on skill; 2 ranks a level
Essential skill; 3 ranks every two levels
used often; 1 rank per level
in frequent use; 1 rank every other level
For all other skills, I would use the base MM bonus provided for the creature. In addition, I consider the MM bonus provided for the creature raw talent, so I add it to any skill development. Creatures do not generally have professions, so no level bonus is applied. However, all creatures in the book are considered average representations of the species, so bonuses for higer stats could be added. I assume average stats are 45-55 in range.
Note that for some creatures, I have created unique individuals for NPC's. When I do this I flesh them out a bit more with stat mods and talents, maybe even a few flaws. Nothing will throw off players like a typical encounter with a typical "whatever" that immediately discovered to be "not so typical", as in HOLY COW, THAT GOBLIN JUST HIT ME WITH A SHOCK BOLT! Or goes imvisible, or jumps high in the trees, or is blessed by a war god and a questing paladin, or a dark wizzards apprentice, etc. This can get real painful when you take an already powerful foe, like a sword demon, and rev em up a bit.
lynn