The college essay requires not only writing skills and self-awareness on the part of the applicant, but also knowledge about the cultural specifics of the American university environment. Applicants who do not have deep roots in this educational system often find it very opaque. Stylistic writing conventions are also very specific to the institution and the process. For example, if you’re applying to UC Berkeley, your essay should be very different from the essay you're writing for Texas A&M. The essay process can hence seem daunting without a guide to help you.
I was an international student myself 18 years ago, and I understand and empathize with your situation and needs. I also understand parental concerns when it comes to optimizing the costs associated with the admissions process. Consulting with me on your essays is a relatively low-cost method to ensure that the tone of your application and the way you represent yourself both match the institutions you are applying to. Please see my services and rates page for more details about the packages I offer.
When should you start working on your essays?
Early, but not too early! Good writing needs time to marinate, but it also needs to sound fresh and urgent. There is no "best" timing, as the process is driven by the needs and personality of the particular student, but in general: students should begin thinking about ideas and topics at least during the summer break before senior year (Grade 12). Many of my students start working on their essays in their junior year, and finish the main Common App essay in the summer. You will have a lot to do in the fall of senior year, so try and finish the main essay before school starts.