Sorry I got messed up a little == Yes of course all problems derive from the lack of education and opportunities, but we should focus more on changing reality than changing laws. Laws can influence people's thoughts, and somehow change the perspectives of people, but it can also have serious side effects that will be more harmful for the girls and women as well as it can always be broke by various ways if people want to.
In Half the Sky Chapter 1 and 2, the author not only vividly mentioned four stories in details, but also traced back to the complex social cause of this phenomenon by analyzing the society from various perspectives. For me, it's really hard to imagine that just as I type on my keyboard, there are millions of girls suffering from both mental and physical pain. Today's slavery isn't treated with gravity because The worst thing is that it has already formed a system that cannot be broken easily, thus I really appreciate those who have never give in, who fight for women rights in such an arduous environment. The brothel system have been worked through years, and the perspectives about enslaved girls have ingrained in the minds of local area. I can't possibly think of a best way to reduce forced prostitution, but I think there is a market because there are needs. So if we can find a method to reduce the needs of costumers. For example, one of the reasons local costumers going to red light districts is that they are unsatisfied with their own conservative marriage; this may be a starting point. Nevertheless, I cannot think any further, because it would be difficult to change their attitude, and what about those women who need to make a living through prostitution; the needs of costumers are essential for them. In conclusion, I don't think the amounts of forced prostituion will reduce without appropriate education and opportunities from the external world.