What should I include or how should I write a letter to a judge in order to get my probation drooped?

Last February I was convicted of a misdemeanour with two years unsupervised probation, the judge said if I did not get in any trouble the first year to write to the court and he would remove the second year and get it removed on my record but I do not what I need to include or if I should hire someone. does anyone know what I should do?