ya, right advice by mumof5. Being stressed, being overweight, and using alcohol or cigarettes all take their toll on your fertility and can decrease your chances of conception.
You can even try having sex a before ovulation. Pregnancy rates peak two days before ovulation. Sperm can live inside the uterus for 24 to 48 hours, which means there will be plenty on hand to greet the egg once ovulation starts. An egg survives for only 12 to 24 hours after ovulation, so if you begin to ovulate in the morning and wait until nighttime to have sex, the egg may lose its viability by the time the sperm gets to it. In addition, cervical mucus starts to become thick and impenetrable right after ovulation, rendering it "hostile" to the passage of sperm.
And the most important thing is, keep sex a fun, honey. Giving yourself a time and not getting stressed is very important, as it can interfere with conception too.