If you think you are ready to have a baby, then there are only a couple of rules that you should follow. First of all, let me begin with what you should not do, as this list is a lot short, so easier to keep in mind.
Unfortunately, oral sex should be avoided. It is not completely forbidden, but if we often engage ourselves in it, then the sperms will always be slow – this is one of the effects of saliva – so the conception becomes less and less likely. As for specific positions on the not-to-do list, there is only one: the woman on top. Probably the reason is obvious. Gravity is working against us, so less sperms will get near the egg, quite likely.
But let me tell you what to do to have more changes to get pregnant. Doggy is the position that can be used in any case, regardless of a woman's anatomy, which might mean an abnormal uterus. Doggy is the only one that fits to those abnormalities, as well. Still, in case of a normal anatomical situation – which couples are usually not aware of – missionary is the position that leads to pregnancy in the most cases. If both are you are on your side, it does not decrease the likelihood of getting pregnant, as well, especially if you also pay attention to what you do after sex.
The woman should stay in bed for 10-20 more minutes, with a pillow under her hips. Before the man leaves the room, he should stay inside her for a short while, as well, and while he is pulling out he should close the labia, so that as much semen can stay inside as possible.
And enjoy it! This is the most important factor! It is not a must, so just have fun just like before!