One of the first things to look for in a modeling contract is the length of your commitment. Some agencies might require a three-year, or even a seven-year, contract. Needless to say, if you become unhappy with how the agency represents you, you're going to remain unhappy for years to come. And breaking a years-long contract might be more complicated and expensive than it's worth, especially if you or your child are only pursuing the business part-time. A contract that is only one to two years in length might be preferable, especially if you are just starting out.
In addition to the term of the contract, you need to clearly understand when and under what circumstances you or the agent can terminate the relationship. Many agencies include a clause that allows either party to end the commitment after, for example, four months to a year, if either party is not satisfied with the number of bookings or amount of earnings. If the contract you are offered does not include such a clause, you can try to negotiate this point. The agency would not want to sign you if it did not believe it could make money from you. Before you sign the contract, use the leverage you have to work out better terms.