Infinite Arrows are great addition for gamers like me that uses long range weapons like bows.

1. First step in this is to enter the Inner Sanctum of the Thieves Guild.
2. There, you will find alot of different characters practicing alchemy whole day.
3. You just need simply to walk to them, and pick all the arrows they have used here.
4. Now just wait for them to shoot more arrows if you really need to.

If you need to duplicate some, simply steal all their equipped arrows while they are sleeping and then equip that character with one of any arrow that you own by placing it on them. Then, they will shoot that one arrow whole time. If they stop practicing, you just need to wait some time, one hour or two will be enough, and they will begin shooting again.

This isn't patched yet, I mean, what they need to patch here anyway right? Just use this exploit wisely, don't be greedy and you will be okay.

Happy bowing.