As an avid Skyrim player, I love sharing tidbits about the game! Now, if it's soul gems you're after, the quickest way to fill them is by using the Soul Trap spell. When casting this on a critter before it meets its untimely end, its soul will funnel directly into one of the empty gems in your inventory. The type of creature determines the gem's size - Petty souls for small creatures, up to Grand souls for the most formidable foes. Also, you can use weapons enchanted with Soul Trap.