Moisture is one the biggest hazards to wood.  Remove moisture often when playing your flute.  You can use a cotton swab to clean out the interior of your flute, or even 'fling' the moisture out by removing the fetish, grasping the end of the sound tube and flinging the flute in a downward motion to expel moisture.   (be careful not to hit anything).  Many times you can expel moisture by giving hard quick breaths on the flute to blow out moisture.  Be sure to dry your flute after playing.  Do not use alcohol to swab out your flute as that tends to dry the wood and promotes cracking.  When finished playing, remove the fetish and allow the flute to air dry, mouthpiece down. 

Occasionally re-oil your flute to help preserve the wood and restore luster.  Use a good non-toxic type oil such as mineral oil or lemon oil.  Swabbing the inside of the sound chamber and the slow air chamber will help prevent water logging on the inside.  Do not use vegetable oils as they can go rancid.  Be sure that the flute is thoroughly dry before oiling.  Allow the flute to dry over night after oiled application.

Remember that wood is very sensitive to the elements.  Avoid long contact with direct sunlight.  Avoid rapid changes in temperature.  Always slowly warm a flute that has been in the cold.  This will help prevent the breath from condensing in the air chamber.

With a little care and common sense, your flute can last for many years and give a lifetime of enjoyment.