Train Mysticism, Combat, And Sneak Skills Simultaneously:

**NOTE: You must have completed the Mages Guild questline for this to work**

Okay, to start off go to the Arena(if you haven't beaten it's storyline) and enter a match. Defeat your opponent and equip the Staff of Worms (SoW). Use the SoW on the fallen warrior and the will be revived for a short while. Cast Soul Trap on them and either kill them or wait for them to die. You will recieve confirmation you have trapped a soul simply repeat this as desired to get exp and fill any Soul Gems you have. This works wonders with the item dupe cheat (see above) and if you have Black Soul Gems. Try doing sneaking around the reanimated person to increase your Sneak level.