Eshu, or how ever you call your Gate Keeper, is in charge of luck. If you want to increase your chances of making a child, you should give offerings to Eshu in his child-like manifestation. So you would bring him more candy, toys, and food prepared as if for an incarnation of Eshu. You can also give gifts to children, especially those who have that flash of Eshu in their eyes. They are hard to miss because they have those moments when they look and move almost like an old person.
Then there is Olokun and Yemaya, mother/father of life on Earth. During an attempt at pregnancy, it is good to bring them fruits with many seeds.
Oshun is in charge of fertility as a blessing. You want to be really good to her so that you can have children and be prosperous enough to provide for them well. Also, be advised that she is prolific in her manifestations on Earth. Many people are children of Oshun. So it is almost inevitable that if you have enough children, at least one will be a child of Oshun. If you make a vow to ensure this child will wear gold, she will bless you a lot. Many people have their child’s ears pierced very young for this reason.
Obatala shapes children in the womb, so it is a good idea to give special offerings to him once you or your client has conceived. If you can, it is a good thing to receive blessings and prophecies from a child of Obatala.
Dada is in charge of childbirth. If you want to have good endurance for labor, give offerings of green, leafy vegetables to Dada.
Osu helps to regulate the menstrual cycle and ovulation, and Orun helps to regulate body temperature, which is important for both women and men trying to make a baby.
Shango improves sex, and stokes the fires of lust.
If you are high risk, or having a problematic pregnancy, you should give offerings to Oya. She is the mother of the abiku. During her human incarnations, she often had trouble having children at first. So she understands.
You should have a bowl for Olokun and/or Yemaya on your altar when you are doing fertility work.
This keeps the energy “fresh” and strong around you. Traditions vary as far as how this bowl should look, and whether or not it should be covered. In some places, the rectangular covered Corningware or Pyrex type dishes are very popular.
If you have some artistic skills, consider making an Olokun/Yemaya from the home made salted play-clay with some sand from the sea shore in it.
Making an Olokun/Yemaya sand figure by the sea is a great activity for a couple trying to make a baby. It is very romantic.
Basically, anything you can do for fertility deities is good.