First, its important to note there are different categories for children of an American citizens. Every category has different processing times due to the visa bulletin. The first category would be an unmarried child under the age of 21. This child is considered an immediate relative, and is not subject to the visa bulletin. It takes anywhere 10-18 months, start to finish. The next category is if you are over 21 years old. You will go into the Visa Bulletin categories. Basically, if you are over 21 we have to check the categories to see when the visas are available and you can check this at the Department of State website. There is also a category for married children. This is going to be a different category with a long waiting time. The answer to this question is there is not really a way to truly expedite this process. You can make a humanitarian request, but we rarely see this approved and this cannot affect the visa date just the processing of the paperwork.