The way to stop child soldiers, child labour, corrupt governments, rebel groups, etc, is not through awareness. It is not through marketing campaigns.
Every problem inherent in Africa today is a direct symptom of a much larger issue: extreme poverty. The eradication of extreme poverty in Africa will lead to the eradication of every other major issue in Africa.
Child soldiers who volunteer into armed conflict (and there are many) do so because of one of two things: they want a better life for their families and themselves, and they see the only way to get a fair share of food and shelter is through the army and armed conflict. Education would help children be self-sufficient and have the knowledge and skills to keep themselves fed and clothed and sheltered, not to mention their families and communities.
Or they join up because of the ideology of the groups. Education would help keep these children from going over to the sides of the rebels or the government army; they would not fall prey to the cause.
The fact that more African children are not educated is a direct symptom of poverty. If money were pumped into these African communities, the number of children who voluntarily enter armed conflict will decrease as they will not have reason.
An end to poverty will lead directly to an end to hunger. Funds will lead to crops being grown, and not just grown, but sustained so as to keep growing and nurturing a community.
An end to poverty will lead to an end of desperation, and thus, an end the wide spread rape of women. Education will make sure these women can lead their own lives, and are not at the mercy of others. An end to the widespread rape of women will lead to a dramatic decrease in HIV/AIDS in Africa. An end to poverty will lead to women having access to contraception, which will again lead to a decrease in HIV/AIDS.
An end to poverty will lead to an educated and self-sufficient African population, which will in turn end to corruption of government and the divergence of funds.
An end to poverty will end all the atrocities found in Africa.
So, instead of tweeting about Kony2012, start sponsoring an African community, start supporting UNICEF and other charities that do not target a symptom, but target instead the disease. You can not fix a cold by taking cough drops, you can not end the use of child soldiers without first ending poverty.