An egg is alive upto 24 hours once it is released. But, a sperm is alive for upto 4-5 days. Thus it is advisable to plan for intercourse 1-2 days before ovulation and during ovulation in order to increase the chances of conception.
Eating healthy, especially during the fertile window will greatly impact the chances of conception. Folic acid supplement is vital for women, while foods like Banana, Asparagus, Ginger improve the sperm health in men.