Planescape: Torment Cheats

In the Sensate Emporium (the private sensory stones),
keep going to Ravel's stone and nodding until you have to speak.
You will gain 6,000 experience points every time. Then, just end
the experience.
Go to the Clerk's Ward at the Coffin Maker's Shop. When you return
and he asks if you found the tomb plans successfully, you will
get 2,000 experience points. Do not continue the conversation
after you get the experience points. Instead, end the conversation
then talk to him again. The same conversation will follow along
with the 2000 experience points. Repeat this as many times as
desired.
You need at least 50 gp to do this, but the money will not be
spent. Go to Yellow Fingers in Ragpickers Square and let him pickpocket
you. Observe him first, to claim experience and pickpocket skill
points. After that, ask him what he is doing. Say that you will
give him money, and give him 50 gp. Suddenly, a zombie will appear
at Morte's Coordinates and you will talk to him as if you were
completing the "Find Where Pharod's Bodies Are Coming From"
Quest. End the conversation. To repeat the glitch, talk to Yellow-Fingers
and do it again. The zombie will ignore you, saying that he is
busy. You will get 200 gp and 750 experience points each time.
When in the prison below Curst, which is accessed through the
entrance in the Outer Curst dump, talk to Trias the Deva after
you get Celestial Fire (which can be found in the middle of the
prison). He will ask you to free him with Celestial Fire. Select
the "Leave" dialogue option (option 3). Go back again
and talk to him. He will say "Do you have another question
mortal?" Select the dialogue options in this order: 1, 2,
1, 1, 2, 1. You should gain 306,250 experience points. Talk to
him again and select dialogue option 2 "Ah well, farewell".
Then, talk to him again and repeat the first sequence (1, 2, 1,
1, 2, 1). Each time you complete the sequence, you will get the
306,250 experience. Use the quick-save after getting the experience
in the event that you select the wrong dialogue option, in which
case reload the game.
Strategy: by Stefanos Koutsoukos

In Curst Revisited (Carceri), you can gain unlimited exp in the warehouse. Talk to Ebb Creaknees and get him to help and then leave. Go back into the warehouse and pause as soon as the loading screen disappears. Scroll over to the right, where Ebb was at first, and he'll still be there. Click on him while the game is still paused, then unpause it and he'll stay for you to talk to. You can do this over and over and gain unlimited experience. It's a slow job, but highly useful if you feel you need to level up.

If you are stuck, need an extra boost of strength, dexterity, constitution or other attribute, or want something but do not know how to get it, see Fell the tattoo man.
Become a Godsman and get the best axe
Talk to the Auctioneer outside the market in the lower ward. Perform the tasks he will ask you to do. The second task will be to deliver a message to a Godsman, therefore granting you passage to the northern gate (in the lower ward). You will eventually meet a man in a room surrounded by other people. Ask him about becoming a Godsman. He will tell you to forge a weapon in the foundry, the first room you saw when you entered the place. Get the items you need from the clerk in the southwest part of the room. Ask Thildin, the muscular man, for some ore. Then, find the only empty barrel and make the weapon of your choice. Report back to the man that told you how to forge the weapon. Next, there will be a murder. You only need to know where the people are -- you already know where Thildon is; the man whose name starts with "S" is in the same room as man that told you how to forge the weapon, and the other is on the balcony just above him. Talk to Thildon one more time and report back to the man that told you how to forge the weapon. Just convince the man in the locked quarters to live. Be nice to him. You will now become a Godsman and have access to the best axe in the game for 5000 GP.

In the Burning corpse inn speak with the female in the dustmans robes in the right corner. Threaten to tell on her disguise and she will offer to give you 50 coins. End the discussion then repeat talking to her. Say the same things over and she will give you another 50 coins, do this until you have whhat you need. NOTE: Do not complete the barkeeps quest as she will leave.