» Sat Jun 02, 2012 11:10 am
Soul Trap:
To fill a soul gem, you have to kill an enemy under the effect of the Soul Trap spell. You can cast Soul trap on them, and kill them within 60 seconds, or much easier: enchant a weapon with soul trap, and use it to kill them. If you don't typically use weapons yourself, you can give your soul trap enchanted weapon and empty soul gems to your follower, and they will take care of it. Then you just take the filled soul gems, and replace them with new empty ones from time to time.
Note that a soul will go into the smallest gem available, but if no smaller one is available, it will go into a larger gem. In other words, if all you have is grand soul gems, and you soul trap and kill a wolf, you will end up with a grand soul gem filled with a petty soul. It is easy to fix this however, just drop improperly filled soul gems on the ground. When you pick them back up, they will be empty again.
Also note that Black soul gems are different. Humanoids (men, mer, Khajit and Argonians -any race that the player can be) have black souls. Their souls can only be captured in black soul gems, and only those souls can be stored there. Black souls are equivalent in power to grand souls. So, in order to get the most powerful soul gems you either have to use black soul gems and kill humanoids or use grand soul gems and kill things like giants and mammoths. Note that dragon souls are never captured by soul gems- they are always absorbed by the Dovahkiin directly.