Staying at a healthy weight, avoiding excessive alcohol and caffeine intake, and having sex daily or every other day may increase a woman's chance of conceiving, according to WebMD. Tracking menstrual cycles and ovulation may also help a woman determine when she is most fertile.
Consuming over 500 milligrams of caffeine, or five cups of coffee per day, may negatively affect female fertility, notes WebMD. Moderate caffeine consumption, or one or two cups of coffee per day, does not have an effect, and women who want to become pregnant should aim to consume no more than 250 milligrams of caffeine each day. Similarly, drinking two or more servings of alcohol daily may decrease a woman's fertility by up to 60 percent. Occasional drinking has not been shown to affect fertility.
Being overweight or underweight may affect a woman's ability to get pregnant, notes Parenting. One study indicated that women who had body mass indices between 25 and 39, which placed them in the overweight or obese categories, took twice as long to conceive than women of normal weight, according to WebMD. Underweight women, with body mass indices under 19, took four times longer to conceive than women of normal weight.