What vitamins to take

My husband and I are trying to conceive our second child. I've only been off the BC for about 3 weeks now. With our first, we weren't really trying and just "let it happen when it happens". So basically we weren't really trying. We are so blessed and thankful for our little girl. Now we are hoping for another. Maybe a boy this time. My question is, are there cortina vitamins I should be taking to help aid the process of conceiving?