Weevil

Best answer as chosen by Asker / Ratings
You gain experience by killing monsters. Kill rare and unique monsters for more experience. They will respawn if you save and exit your game, then reload it.
Also, if you've explored an area previously, head for the shrines (bring up the map and look for the brown squares) and check for an 'Experience Shrine'. Activate it, then start killing monsters.

Gold is dropped from monsters, or found in chests, under rocks, etc. You can get monsters to drop more gold than normal if you have a magic item or talisman with this property.
You will find that most of your gold will be obtained by selling all the useless junk (weapons, armor, potions, scrolls, etc.) to the merchants.