Any advice?

My boyfriend and I have been together for over a year (yes I know that's not long) but we have decided we want to start trying to have kids. I have one already and she wants a sibling which makes it better. However we have been looking up things to help us increase our chances. We look at the calendar to see when I'm ovulating, we changed our diet, I've been losing weight. What else can I do to improve our chances? Any advice would be great