For enhancing the chances of conceiving you should have sex during ovulation days. You can try having sex regularly five to six days prior to the expected date of ovulation and continue daily until the day after you ovulate. You should start taking folic acid, exercise daily and reach your optimal weight. Take a healthy diet. If you are not able to conceive for more than 6 months you should consult a gynecologist for an evaluation. The reason of not getting pregnant may be because of medical problem either in you or your partner. You and your partner both may need to be investigated. Some tests may be necessary like semen analysis in men and to check for ovulation in women. Keep me posted.
Best wishes and regards!