What are a few proven natural ways a woman can increase her fertility?

Lifestyle changes .. Lifestyle changes that may help include aiming for a normal weight if you're underweight or overweight, stopping smoking, avoiding heavy alcohol use, and avoiding illegal drugs as well as prescription narcotic pain medications. High caffeine intake may increase the risk of miscarriage, stick to one cup of brewed coffee a day and decaf for the rest (no espresso). No well-proven herbs or supplements.
Nutrition and stress. Good nutrition, normal weight, regular intercourse, stress reduction.