You can optimize your chances of getting pregnant in a number of ways.
Exercise moderately. Do not exercise so heavily that your menstrual periods are infrequent or absent.
Avoid extremes of weight. An optimum body mass index (BMI) is at least 20 and below 27.
Avoid alcohol, smoking and drugs.
Avoid too much caffeine. Do not drink more than one cup of coffee per day.
Review your medicines with your doctor. Some medications can affect your ability to conceive or carry a normal pregnancy.
A "fertility diet". The following nutritional advice seems to be associated with improved fertility:
Avoiding trans fats (check the Nutrition Facts labels on foods)
Eating more beans, nuts and other fertility-boosting plant protein
Eating more whole grains
Avoiding sugary sodas
Having a glass of whole milk and other full-fat dairy food every day (even including an occasional small bowl of ice cream)
Some treatments for cancer can cause infertility. Certain techniques allow a woman planning to undergo chemotherapy or radiation to later have a baby from her own egg. Discuss these with your doctor before beginning cancer treatment.