Is there a special way to conceive a baby for sure?

No: Conception involves 2 parties, a sperm and an egg. There is no 'sure' way to conceive other than to have sex, preferably every other day, around the time of ovulation. For a woman, knowing when you ovulate can, of course, help immensely in this process. There are apps that help you (check basal body temp every morning, for instance) as well as ovulation predictor kits. Good luck!