any advice on how to get pregnant?

I'm 20 years old, I've been married for over a year. I've never been on birth control, we've never used a condom, (TMI) but he always finishes in me different positions, I've never smoked, I've never drank, I don't drink dark soda, I've never had coffee, I do like exercise almost everyday, & I get 8-10 hours of sleep. what am I doing wrong? is there any food that helps? certain sex days? positions, or medicines? I'm so lost and I want a baby!!