Stealing as a newbie feef
Stealing, or rather, snatching, is really one of the easiest ways you can get money as a newbie thief, and here's how you can start filling your quota ASAP.
1. Get the Snatch Command
If you got the 5 levels of covert skill in Pumpkin Town, you can get the snatch command. Just go to Kordane and ask him nicely to teach you. Don't worry about not being able to fill your quota. You're more likely to wish you had a bigger quota.
2. Get Your Licence
It is easier to steal in Ankh Morpork, so do remember to tell Kordane that you've returned from your leave of absence unless you want to end up on the river.
3. Get Healthier
If you have any exp to spare, it may be advisable to train up some levels of other.health just in case you fail a snatch horribly. About 1000 hp is okay for a start. This isn't necessary, but it's safer if you do.
4. Stash Your Weapons
Priests can make you fumble them. Remember they stay agro for a bit after snatching.
5. Consider Before Snatching
Consider the NPCs before snatching. If it says "<target> is into the don't think about it region" or "You would have to be utterly insane to attack <target>", you may wish to think twice before trying to snatch in case you don't manage to run away before getting hit a couple of times.
6. Snatch Money
I suggest you stick to money for a while unless you actually want the item(s) for keeps. After the guild tithe, you have 70% of the money you steal. If you snatch or shoplift items, after the guild's 30%, not laundered ?%, not mended / fixed ?%, you won't have much left.
And no, you do NOT want to snatch any relic, holy symbol, and other priestly items while in AM. On a side note, yellow stone rings are also not worth shoplifting in AM. (These items are perfectly good out of AM though.)
7. Keep Running
After snatching, keep running. You need to move at least 1 more room away, 2 rooms if you failed and didn't manage to run out of the first room.
8. Suggested NPCs
Lawyers, accountants, merchants, traders, bodyguards, beggars, priests...