Stop drinking and smoking tobacco, make sure you're getting proper nutrition from real food with limited ingredients, cut down on dairy, try to get some exercise, and have sex every 1-2 days, especially when you're ovulating. After sex, try to lay with your hips elevated for 20 minutes. Also, make sure your partner isn't smoking tobacco or marijuana. Both of those are known to decrease the quality of sperm. Most importantly, don't stress about it. Good luck!