Begging taken from the Second Age Play Guide (printed in 1998)
Use the skill, then click on an NPC in your immediate vicinity. If successful, you will be given some money (if the NPC has some to share)
The maximum amount you can receive per Begging attempt is 10% of the NPC's cash on hand.
A successful attempt is indicated by the NPC saying "I feel sorry for thee", a small amount of gold appearing in your backpack, and a loss of karma. This karma loss will continue for each successful attempt up to 'Scoundrel'. The begging skill is directly affected by your karma, and the likelihood of a successful attempt is much lower if your karma is negative.
To counteract this, it may be wise to include a combat skill in your beggar's template in order to raise karma by killing rats and other monsters.
Once the NPC's cash on hand is depleted to 9gp, you can no longer receive money from them, but you can still gain from the attempt.
To macro begging, simply make a macro to beg from an NPC, pause 13 seconds, and loop. This is most effective if you can block the NPC in somewhere that prevents them from moving away.