I think the government have a huge part to play in birth control. Not actually by placing strict rules but through proper sensitization.
Adding to that another problem of Nigeria is resource mismanagement. The overcrowding in Lagos is because of undiversified business hub making almost everyone to cluster in the Lagos city.
Yes. Proper education and enlightenment. I think that's the most effective thing that they can do, alongside being transparent with resource management. I am curious about where you are from, though.