What Can A Woman Do To Increase Her Progesterone Levels?

It depends on the cause.  It is natural for progesterone to decline in women's bodies as they get older; this is hard to fight.  The decline leads to estrogen dominance, which in turn leads to many pre-menopausal symptoms.  

Nevertheless, a woman can try to slow the process.  Several vitamins and minerals are thought to generally increase progesterone production; Vitamin C, Vitamin E, Vitamin B6, Magnesium and Zinc. At least, it is known that women deficient in these nutrients are more likely to have relatively low progesterone levels.  

Taking vitamins may not be the solution, though.  High dietary sugar intake can lead to Magnesium deficiency.  Excess iron or Vitamin B6 intake can lead to zinc deficiency.  It's hard to balance these out when taken as vitamin supplements.  That's why that old adage about "a healthy balanced diet" is true; you can't just take vitamin pills to make up for a lousy diet.

Herbs and supplements that may help:
Vitex Agnus Castus (or "Chasteberry")
Maca (a South American root vegetable)
Liquorice tea

Also, try to avoid being too fat, and obvious sources of phyto-estrogens.  Phyto-estrogens are chemicals in pesticides, perfumed products, birth control, and meat from hormone-fed animals.

Stress decreases progesterone levels, as does high caffeine intake.

They say that eating the right types of certain foods can help you such as Garlic etc. Look through super foods on the internet.