Below is an example of an essay with the thesis in bold (with comments afterward):
There is a great deal of controversy among parents as to whether children should hold a paying job while in high school. Some parents believe that working while in school is a valuable experience; others believe that the importance of good grades supersedes any value that a job might offer. I think that working while in school can be very beneficial to students and provide them with the skills that might enhance their "formal" education.
One of the skills is time management. Learning how to balance your activities and obligations is essential as an adult. It is invaluable to know what you can handle and when you are taking on too much. When I got a job in high school, I began to realize the importance of using my time wisely since I had less of it to throw around. I think that I gained a lot from having to make those decisions as well as earning my own money.
Another benefit is that students can develop a work ethic that can be applied to their academics or any task they choose to take on. Understanding the importance of working hard, doing a good job, and being responsible are assets to any endeavor. Students often develop confidence from being counted on to get something done and then rising to that challenge. Additionally, learning to take pride in your work is really important. When you care about something, your performance reflects that. Academic success largely depends upon this same kind of pride and confidence.
Ultimately, I believe that whether a child should work while in school depends on the child. Some children feel that they can't handle the responsibility, while others are willing to try. I think that students stand to gain a lot from working, but should be able to make that choice for themselves in the end.