3rd time ttc and nothing - losing hope

This will be my 3rd time ttc and I feel so helpless I got pregnant right away with my first 2.5 years ago. Now I see it’s so hard. We did everyhing right. I don’t know where I’m going wrong. We are both healthy there should be no reason why we can’t conceive try after try. I use opks, baby dance right before I got my postive and after my postive. Even used preseed. Please guide me how to get a bfp this month.