General Method Description

Master farmers are a major source of seeds for farming; when you pickpocket one you can get any seed but tree seeds, or you may be stunned and hit for 3 damage if you fail. Most of the seeds you get are junk, but you do get some good seeds as well, such as ranarr seeds and watermelon seeds, and even mid-level seeds like sweetcorn add up in value quickly.

A nice place to pickpocket master farmers is in the Draynor Village marketplace, since it is literally right next to a bank. At level 50 Thieving you will fail fairly often, but it's still worth doing, and the gloves of silence do help. Unfortunately you need level 65 Crafting to repair these, so I assume you will use them until they wear out and then put on a new pair. With level 65 Crafting you can repair these using dark kebbit fur, assuming you notice they are wearing out before they disappear. Also, at this level I recommend using a bunyip familiar to aid in healing damage. This is not so much to save money (cakes are cheap) but to let you avoid having to run back to the bank so often for more food, and to free up more inventory space for seeds.

At level 70 Thieving you should fail infrequently, and at level 90 quite rarely. Note that since my Thieving level is well below 90, the very high level results are "guesstimated".

At very high levels, the Ardougne Cloak 3 is supposed to improve your chances of success in Thieving. I haven't been able to verify this with my tests -- the random number generator seems to dwarf the effect -- but there's no harm in wearing it.