Baldur's Gate
Easy Level Gain and Money in Multiplayer Games:
When starting the game in the Town of Candlekeep do all the "Quests"
(errands for guards, and other characters). That means anything that
gives experience. Once you have done this go to the Character Screen
and export your character.
End the game and start a new game and import character. This allows
you to start the game with the amount of experience that you had
gained. Repeat until satisfied.
If you started game as thief or strong warrior and thief has high
enough lockpicking skills. You may bust or unlock a chest in the
starting Inn on the second floor, that contains a gem that is worth
1,000 gold peices.
Easy Money:
Put potions in all of your quick item slots. Switch to the inventory
screen and replace the rightmost potion with a gem. Now return to
the adventure screen. Notice the picture of the potion you replaced
with a gem still looks like a potion. Click it multiple times and
return to the inventory screen. The number of gems should change
from 1 to no number at all. Switch back to adventure screen and
repeat the process...now you should have 65,000 gems.
Object Duplication in Multiplayer:
This trick only works in multiplayer games.
Export the character that has the object(s) you wish to duplicate,
export said character to a vacant slot. Then, when in a game,
import that character to get the items in his/her inventory. The
same character can be imported multiple times to the same party.