How long? Most experts consider looking into a fertility workup if you have been trying without success for a year. Such a workup involves both husband and wife, because the issue may be with either. A regional fertility center or local OBGYN and Urologist can start the process.
More info needed. Depending on your age, how long you've been trying and whether or not you have suspicions of problems in certain areas (sperm, egg, tubes, uterus), your best strategy may be to patiently keep trying or to explore some medical assistance. More information is needed to guide you specifically.