What to do about overpopulation?

A few days ago, a Facebook smart alec responded to one of mine posting about the how the current environmental was a symptom of our planet's growing overpopulation.

The man said:
“What do you want to do? Kill have of them [the population], obviously all the 'others'”?

This was my response:
“Good point! But before suggesting any genocide, let's talk first about slowing down the growth of the population. When it can be stopped, and always gradually, start working on reducting the population, a stop not only desirable, but necessary. That said, a pro-birth push, this reduction will obviously be much slower and require both attrition through natural death and birth control, a much more complicated and time consuming process.”

What can we do practically? Become aware of the problem.

• This is not presently not the case; No one really wants to talk about it, because the topic is taboo, as it's tightly controlled by all religious leaders as well as Wall Street (population growth being the cornerstone of the capitalistic system). 
• Do something about it; the Chinese started right by setting a one-birth ceiling per household, promote family planning, etc. 
• Spread the word about the dangers of overpopulation and their consequence and foster a conversation among civil and religious communities. 
• Set realistic targets at the international level (UN) 
• Decide on a long-term strategy. For example, economic aid to developing countries linked to robust family planning, etc. 
• And you, what's your suggestion ?