If I soul tap a lesser soul but have a greater or larger soul gem open, will the soul fill that gem and waste the greater soul gem? I haven't done too much in enchanting, but sometimes I see a petty soul fill a common soul gem in my inventory.

It will go to the smallest gem available to hold it, so yes, exercise caution.

@jaycrockett: That's what I was afraid of. I've got the soul trap enchantment on my main weapon so I'll have to make a new one. Also, how do you know what level of souls the enemies are?

@SilverBulletKY said:

@jaycrockett: That's what I was afraid of. I've got the soul trap enchantment on my main weapon so I'll have to make a new one. Also, how do you know what level of souls the enemies are?

http://www.uesp.net/wiki/Skyrim:Souls

@SilverBulletKY said:

@jaycrockett: That's what I was afraid of. I've got the soul trap enchantment on my main weapon so I'll have to make a new one. Also, how do you know what level of souls the enemies are?

I'd love to know if there is some trick to this as well. I just kind of guess based on how tough they are to kill from past experience and switch to a non soul trapping weapon for any easy enemies when I run out of empty petty gems.

I hadn't really planned on soul trapping until I got Azura's Star. Then you can just dump a lesser soul to an item and keep going.

@Axxol said:

@SilverBulletKY said:

@jaycrockett: That's what I was afraid of. I've got the soul trap enchantment on my main weapon so I'll have to make a new one. Also, how do you know what level of souls the enemies are?

http://www.uesp.net/wiki/Skyrim:Souls

Interesting. I thought there would have been more creatures in the game. Also only 8 of them give grand souls.

@SilverBulletKY said:

@Axxol said:

@SilverBulletKY said:

@jaycrockett: That's what I was afraid of. I've got the soul trap enchantment on my main weapon so I'll have to make a new one. Also, how do you know what level of souls the enemies are?

http://www.uesp.net/wiki/Skyrim:Souls

Interesting. I thought there would have been more creatures in the game. Also only 8 of them give grand souls.

8 not including all of the npc's you can kill to farm grand souls. That's more than enough.