I would start with a vivid picture/description of what you see in a child beauty pageant. You could watch "Toddlers and Tiaras" for inspiration. Closely watch the girls as they walk the stage. What are they wearing? What does their makeup look like? Pay particular attention to their parents and coaches. Who wants it more? If you start your paper talking about early exploitation and then continue with where it leads in the future, you'll have a great paper.
The Ramsay opening is a dynamite one. Honestly, this is one of the most compelling openings to any paper about beauty pageants. Another opening would be the "Little Miss Sunshine" competition scene from "Little Miss Sunshine." The idea that the dysfunctional family can come together and bond over their opposition to the objectification of the little girl would be a good opening. I think that the idea from both of these would be that beauty pageants do, to a large extent, objectify women to a great extent. Perhaps another opening would be in the fact that there can only be one winner and all of the women who do in fact fail to get into the finals are declared "losers." By most standards, those women who lose are quite beautiful from an aesthetic standpoint. If these women are declared "losers," one can only think of the women who are struggling with their own sense of physical beauty. What does it say to them? How does this impact their own sense of self? When beauty is something external, there can be little in the way of emotional satisfaction if this is the only standard held. This could be another interesting opening that could pull the reader into the piece.
A great attention grabber is citing a newspaper article about someone who was a famous beauty queen. For example, if you want to write that being a beauty queen is exploitive you could start off with a news article about Gene Benet Ramsay. (Not sure of I spelled her name correctly.) She was that little girl who was found murdered. She was always performing in child beauty pageants. The news did a big story on her showing the outfits she wore at the beauty pageants. Some of the outfits were really sexual, suggesting a woman in a child's body. If you started your essay with a news story citing a famous beauty pageant queen, then I think that would be good.
You could also say that beauty pageants are always for the viewing pleasure of a culture that is created by men. And then you can say that this is no different than pornography. Or that it is only different by degree of difference. If you make this comparision, it might be thought provoking. Also, you can called it legalized pornography. This line of reasong will probably be controversial, but that might be what you want, especially if you want to start a discussion by grabbing the attention of the audience. Now, if you couple this with the previous person's ideas, then it can truly be powerful.
The word exploit has two slightly different meanings. In general it means making use of something or putting something to some useful purpose. For example, we speak of exploiting a gold mine to produce gold. The other meaning has a negatively charged emotional connotations. As per this meaning, exploitation means to make unfair use of something for selfish purpose.
If we allege that beauty pageants make unfair use of females, then we should should be able to specify in what way the females are being used unfairly. There are many ladies who work on job that require much harder work with much less pay than a ladies who may be be a part of a beauty pageants. For example, a lady who may be employed by a small factory for assembly work. If we don't consider that millions of such ladies are exploited, then it is rather puzzling for in what way ladies working on beauty pageants are exploited.