Fill the oil lamp with oil. Carefully lift the glass chimney off the lamp and set it aside. Unscrew the burner--the part that holds the wick--from the lamp and remove it. Fill the lamp with oil until it reaches a half-inch below the top of the lamp bowl. Screw the burner back onto the base of the lamp.
Clean the glass chimney if it's soiled with soot and smoke. Carefully stuff pieces of newspaper into the chimney as you turn it. When the glass is clean, remove the newspaper and discard it.
Trim the wick. Turn the knob on the burner to raise the wick up about a half-inch. Cut off the burnt part of the wick with a pair of sharp scissors. Lower the wick until only a quarter-inch is sticking out.
Light the wick with a match or lighter. Adjust the wick by raising or lowering it so the flame burns properly. If it smokes, the wick is too high and needs to be lowered. Turn it down just enough that the smoking stops. Replace the glass chimney on the base of the oil lamp.
Extinguish an oil lamp by cupping your hand at the back of the chimney top. Blow toward your hand. The air will put the flame out.